Novel adenine derivatives

ABSTRACT

The present invention relates to compounds of formula (I): 
     
       
         
         
             
             
         
       
     
     wherein R 1  is C 1-6 alkylamino, or C 1-6 alkoxy; R 2  is a group having the structure: 
     
       
         
         
             
             
         
       
     
     n is an integer having a value of 1 to 6; Het is a 6-membered saturated heterocycle containing one nitrogen atom wherein Het is attached to the —(CH 2 ) n — moiety at any carbon atom of the heterocycle; R 3  is hydrogen, C 1-8 alkyl, or C 3-7 cycloalkylC 0-6 alkyl; and salts thereof are inducers of human interferon. Compounds which induce human interferon may be useful in the treatment of various disorders, for example the treatment of allergic diseases and other inflammatory conditions for example allergic rhinitis and asthma, the treatment of infectious diseases and cancer, and may also be useful as vaccine adjuvants.

BACKGROUND OF THE INVENTION

The present invention relates to compounds, processes for theirpreparation, compositions containing them, to their use in the treatmentof various disorders in particular allergic diseases and otherinflammatory conditions for example allergic rhinitis and asthma,infectious diseases, cancer, and as vaccine adjuvants.

Vertebrates are constantly threatened by the invasion of microorganismsand have evolved mechanisms of immune defence to eliminate infectivepathogens. In mammals, this immune system comprises two branches; innateimmunity and acquired immunity. The first line of host defence is theinnate immune system, which is mediated by macrophages and dendriticcells. Acquired immunity involves the elimination of pathogens at thelate stages of infection and also enables the generation ofimmunological memory. Acquired immunity is highly specific, due to thevast repertoire of lymphocytes with antigen-specific receptors that haveundergone gene rearrangement.

The innate immune response was originally thought to be non-specific,but is now known to be able to discriminate between self and a varietyof pathogens. The innate immune system recognises microbes via a limitednumber of germline-encoded Pattern-Recognition Receptors (PRRs) whichhave a number of important characteristics.

Toll-like receptors (TLRs) are a family of ten Pattern RecognitionReceptors described in man. TLRs are expressed predominantly by innateimmune cells where their rôle is to monitor the environment for signs ofinfection and, on activation, mobilise defence mechanisms aimed at theelimination of invading pathogens. The early innate immune-responsestriggered by TLRs limit the spread of infection, while thepro-inflammatory cytokines and chemokines that they induce lead torecruitment and activation of antigen presenting cells, B cells, and Tcells. The TLRs can modulate the nature of the adaptive immune-responsesto give appropriate protection via dendritic cell-activation andcytokine release (Akira S. et al, Nat. Immunol., 2001: 2, 675-680). Theprofile of the response seen from different TLR agonists depends on thecell type activated.

TLR7 is a member of the subgroup of TLRs (TLRs 3, 7, 8, and 9),localised in the endosomal compartment of cells which have becomespecialised to detect non-self nucleic acids. TLR7 plays a key rôle inanti-viral defence via the recognition of ssRNA (Diebold S. S. et al,Science, 2004: 303, 1529-1531; and Lund J. M. et al, PNAS, 2004: 101,5598-5603). TLR7 has a restricted expression-profile in man and isexpressed predominantly by B cells and plasmacytoid dendritic cells(pDC), and to a lesser extent by monocytes. Plasmacytoid DCs are aunique population of lymphoid-derived dendritic cells (0.2-0.8% ofPeripheral Blood Mononuclear Cells (PBMCs)) which are the primary typeinterferon-producing cells secreting high levels of interferon-alpha(IFNα) and interferon-beta (IFNβ) in response to viral infections (LiuY-J, Annu. Rev. Immunol., 2005: 23, 275-306).

Allergic diseases are associated with a Th2-biased immune-response toallergens. Th2 responses are associated with raised levels of IgE,which, via its effects on mast cells, promotes a hypersensitivity toallergens, resulting in the symptoms seen, for example, in allergicrhinitis. In healthy individuals the immune-response to allergens ismore balanced with a mixed Th2/Th1 and regulatory T cell response. TLR7ligands have been shown to reduce Th2 cytokine and enhance Th1 cytokinerelease in vitro and to ameliorate Th2-type inflammatory responses inallergic lung models in vivo (Fili L. et al, J. All. Clin. Immunol.,2006: 118, 511-517; Moisan J. et al, Am. J. Physiol. Lung Cell Mol.Physiol., 2006: 290, L987-995; Tao et al, Chin. Med. J., 2006: 119,640-648). Thus TLR7 ligands have the potential to rebalance theimmune-response seen in allergic individuals and lead to diseasemodification.

Central to the generation of an effective innate immune response inmammals are mechanisms which bring about the induction of interferonsand other cytokines which act upon cells to induce a number of effects.These effects can include the activation of anti-infective geneexpression, the activation of antigen presentation in cells to drivestrong antigen-specific immunity and the promotion of phagocytosis inphagocytic cells.

Interferon was first described as a substance which could protect cellsfrom viral infection (Isaacs & Lindemann, J. Virus Interference. Proc.R. Soc. Lon. Ser. B. Biol. Sci. 1957: 147, 258-267). In man, the type Iinterferons are a family of related proteins encoded by genes onchromosome 9 and encoding at least 13 isoforms of interferon alpha(IFNα) and one isoform of interferon beta (IFNβ). Recombinant IFNα wasthe first approved biological therapeutic and has become an importanttherapy in viral infections and in cancer. As well as direct antiviralactivity on cells, interferons are known to be potent modulators of theimmune response, acting on cells of the immune system.

As a first-line therapy for hepatitis C virus (HCV) disease, interferoncombinations can be highly effective at reducing viral load and in somesubjects in eliminating viral replication. However, many patients failto show a sustained viral response and in these patients viral load isnot controlled. Additionally, therapy with injected interferon may beassociated with a number of unwanted adverse effects which are shown toaffect compliance (Dudley T, et al, Gut., 2006: 55(9), 1362-3).

Administration of a small molecule compound which could stimulate theinnate immune response, including the activation of type I interferonsand other cytokines, could become an important strategy for thetreatment or prevention of human diseases including viral infections.This type of immunomodulatory strategy has the potential to identifycompounds which may be useful not only in infectious diseases but alsoin cancer (Krieg. Curr. Oncol. Rep., 2004: 6(2), 88-95), allergicdiseases (Moisan J. et al, Am. J. Physiol. Lung Cell Mol. Physiol.,2006: 290, L987-995), other inflammatory conditions such as irritablebowel disease (Rakoff-Nahoum S., Cell., 2004, 23, 118(2): 229-41), andas vaccine adjuvants (Persing et al. Trends Microbiol. 2002: 10(10Suppl), S32-7).

In animal models, imiquimod demonstrated adjuvant activities eithertopically (Adams S. et al, J. Immunol., 2008, 181:776-84; Johnston D. etal, Vaccine, 2006, 24:1958-65), or systemically (Fransen F. et al,Infect. Immun., 2007, 75:5939-46). Resiquimod and other related TLR7/8agonists have also been shown to display adjuvant activity (Ma R. et al,Biochem. Biophys. Res. Commun., 2007, 361:537-42; Wille-Reece U. et al,Proc. Natl. Acad. Sci. USA, 2005, 102:15190-4; Wille-Reece U. et al,US2006045885 A1).

Mechanisms which lead to induction of type I interferons are only partlyunderstood. One mechanism which can lead to the induction of interferonin many cell types is the recognition of double-stranded viral RNA bythe RNA helicases RIG-I and MDA5. This mechanism is thought to be theprimary mechanism by which interferons are induced by Sendai virusinfection of cells.

Further mechanisms for the induction of interferons are viaTLR-dependent signalling events. In man, plasmacytoid dendritic cells(pDCs) are professional interferon-producing cells, able to make largeamounts of interferons in response to, for example, viral infection.These pDCs are shown to preferentially express TLR7 and TLR9 andstimulation of these receptors with viral RNA or DNA respectively caninduce expression of interferon alpha.

Oligonucleotide agonists of TLR7 and TLR9, and small moleculepurine-based agonists of TLR7 have been described which can induceinterferon alpha from these cell types in animals and in man (Takeda K.et al, Annu. Rev. Immunol., 2003: 21, 335-76). TLR7 agonists includeimidazoquinoline compounds such as imiquimod and resiquimod, oxoadenineanalogues and also nucleoside analogues such as loxoribine and7-thia-8-oxoguanosine which have long been known to induce interferonalpha. International Patent Application publication number WO2007/034882 (Dainippon Sumitomo Pharma Co. Ltd./AstraZeneca Aktiebolag)discloses certain adenine compounds useful as medicine.

It remains unclear how small molecule purine-like compounds can inducetype I interferons and other cytokines since the molecular targets ofthese known inducers have not been identified. However, an assaystrategy has been developed to characterise small molecule inducers ofhuman interferon IFNα (regardless of mechanism) which is based onstimulation of primary human donor cells with compounds, and isdisclosed herein.

BRIEF DESCRIPTION OF THE INVENTION

Certain compounds of the invention have been shown to be inducers ofhuman interferon and may possess an improved profile with respect toknown inducers of human interferon, for example enhanced potency, andmay show enhanced selectivity for IFNα with respect to TNFα. Forexample, certain compounds of the invention indicate greater than1000-fold selectivity for IFNα induction over TNFα induction. Compoundswhich induce human interferon may be useful in the treatment of variousdisorders, for example the treatment of allergic diseases and otherinflammatory conditions for example allergic rhinitis and asthma, thetreatment of infectious diseases and cancer, and may also be useful asvaccine adjuvants.

Certain compounds of the invention are potent immunomodulators andaccordingly, care should be exercised in their handling.

SUMMARY OF THE INVENTION

In a first aspect, there is provided a method of treatment of allergicdiseases and other inflammatory conditions, infectious diseases, andcancer, which method comprises administering to a human subject in needthereof a therapeutically-effective amount of a compound of formula (I):

wherein;

-   -   R¹ is C₁₋₆alkylamino, or C₁₋₆alkoxy;    -   R² is a group having the structure:

-   -   n is an integer having a value of 1 to 6;    -   Het is a 6-membered saturated heterocycle containing one        nitrogen atom wherein Het is attached to the —(CH₂)_(n)— moiety        at any carbon atom of the heterocycle;    -   R³ is hydrogen, C₁₋₈alkyl, or C₃₋₇cycloalkylC₀₋₆alkyl;        or a pharmaceutically acceptable salt thereof.

In a further embodiment, R¹ is n-butyloxy.

In a further embodiment, R¹ is (1S)-1-methylbutoxy.

In a further embodiment, R¹ is n-butylamino.

In a further embodiment, R¹ is (1-methylethyl)oxy.

In a further embodiment, n is 1.

In a further embodiment, n is 2.

In a further embodiment, n is 3.

In a further embodiment, n is 4.

In a further embodiment, n is 5.

In a further embodiment, n is 6.

In a further embodiment, n is 2, 3, or 4.

In a further embodiment, Het is attached to the —(CH₂)_(n)— moiety atthe 2-position of the heterocycle.

In a further embodiment, Het is attached to the —(CH₂)_(n)— moiety atthe 3-position of the heterocycle.

In a further embodiment, Het is attached to the —(CH₂)_(n)— moiety atthe 4-position of the heterocycle.

In a further embodiment, when Het is attached to the —(CH₂)_(n)— moietyat the 3-position of the heterocycle, then the stereochemistry at the3-position of the heterocycle is (R,S).

In a further embodiment, when Het is attached to the —(CH₂)_(n)— moietyat the 3-position of the heterocycle, then the stereochemistry at the3-position of the heterocycle is (R).

In a further embodiment, when Het is attached to the —(CH₂)_(n)— moietyat the 3-position of the heterocycle, then the stereochemistry at the3-position of the heterocycle is (S).

In a further embodiment, R³ is ethyl.

In a further embodiment, R³ is a hydrogen atom.

In a further embodiment, R³ is n-propyl.

In a further embodiment, R³ is 1-methylethyl.

In a further embodiment, R³ is n-butyl.

In a further embodiment, R³ is 2-methylpropyl.

In a further embodiment, R³ is 3-methylbutyl.

In a further embodiment, R³ is cyclopentyl.

In a further embodiment, R³ is cyclopentylmethyl.

In a further embodiment, R³ is 2-cyclohexylethyl.

In a further embodiment, R³ is 1-ethylpropyl.

In a further embodiment, R³ is cyclohexyl.

In a further aspect, there are provided compounds of formula (I′):

wherein;

-   -   R^(1′) is C₁₋₆alkylamino, or C₁₋₆alkoxy;    -   R^(2′) is a group having the structure:

-   -   n′ is an integer having a value of 1 to 6;    -   Het′ is a 6-membered saturated heterocycle containing one        nitrogen atom wherein Het′ is attached to the —(CH₂)_(n′)—        moiety at any carbon atom of the heterocycle;    -   R³ is hydrogen, C₁₋₈alkyl, or C₃₋₇cycloalkylC₀₋₆alkyl;        and salts thereof;        with the proviso that        2-butoxy-7,8-dihydro-9-[2-(piperidin-2-yl)ethyl]-8-oxoadenine is        excluded.

In a further embodiment, R^(1′) is n-butyloxy.

In a further embodiment, R^(1′) is (1S)-1-methylbutoxy.

In a further embodiment, R^(1′) is n-butylamino.

In a further embodiment, R^(1′) is (1-methylethyl)oxy.

In a further embodiment, n′ is 1.

In a further embodiment, n′ is 2.

In a further embodiment, n′ is 3.

In a further embodiment, n′ is 4.

In a further embodiment, n′ is 5.

In a further embodiment, n′ is 6.

In a further embodiment, n′ is 2, 3, or 4.

In a further embodiment, Het′ is attached to the —(CH₂)_(n′)— moiety atthe 2-position of the heterocycle.

In a further embodiment, Het′ is attached to the —(CH₂)_(n′)— moiety atthe 3-position of the heterocycle.

In a further embodiment, Het′ is attached to the —(CH₂)_(n′)— moiety atthe 4-position of the heterocycle.

In a further embodiment, when Het′ is attached to the —(CH₂)_(n′)—moiety at the 3-position of the heterocycle, then the stereochemistry atthe 3-position of the heterocycle is (R,S).

In a further embodiment, when Het′ is attached to the —(CH₂)_(n′)—moiety at the 3-position of the heterocycle, then the stereochemistry atthe 3-position of the heterocycle is (R).

In a further embodiment, when Het′ is attached to the —(CH₂)_(n′)—moiety at the 3-position of the heterocycle, then the stereochemistry atthe 3-position of the heterocycle is (S).

In a further embodiment, R^(3′) is ethyl.

In a further embodiment, R^(3′) is a hydrogen atom.

In a further embodiment, R^(3′) is n-propyl.

In a further embodiment, R^(3′) is 1-methylethyl.

In a further embodiment, R^(3′) is n-butyl.

In a further embodiment, R^(3′) is 2-methylpropyl.

In a further embodiment, R^(3′) is 3-methylbutyl.

In a further embodiment, R^(3′) is cyclopentyl.

In a further embodiment, R^(3′) is cyclopentylmethyl.

In a further embodiment, R^(3′) is 2-cyclohexylethyl.

In a further embodiment, R^(3′) is 1-ethylpropyl.

In a further embodiment, R^(3′) is cyclohexyl.

Examples of compounds of formula (I) are provided in the following list,and form a further aspect of the invention:

-   6-amino-2-butoxy-9-[(1-ethyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butylamino)-9-[(1-ethyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   2-(butyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine;-   2-(butyloxy)-9-[(3S)-3-piperidinylmethyl]-9H-purin-6-amine;-   2-(butyloxy)-9-[(3R)-3-piperidinylmethyl]-9H-purin-6-amine;-   2-(butyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amine;-   2-(butyloxy)-9-[(1-ethyl-4-piperidinyl)methyl]-9H-purin-6-amine;-   2-(butyloxy)-9-[2-(1-ethyl-4-piperidinyl)ethyl]-9H-purin-6-amine;-   2-(butyloxy)-9-[3-(1-ethyl-4-piperidinyl)propyl]-9H-purin-6-amine;-   6-amino-2-(butyloxy)-9-[4-(1-ethyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(2-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-ethyl-2-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-ethyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-propyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(1-methylethyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-butyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(2-methylpropyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(3-methylbutyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-cyclopentyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(cyclopentylmethyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(2-cyclohexylethyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[(1-propyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{[1-(1-methylethyl)-3-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[(1-butyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{[1-(2-methylpropyl)-3-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{[1-(3-methylbutyl)-3-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[(1-cyclopentyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-ethyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-propyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(1-methylethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-butyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(2-methylpropyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(1-ethylpropyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-cyclopentyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(cyclopentylmethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-cyclohexyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(2-cyclohexylethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[2-(3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-9-[2-(1-ethyl-3-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-ethyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-propyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(1-methylethyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-butyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(2-methylpropyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(3-methylbutyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-cyclopentyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(cyclopentylmethyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(2-cyclohexylethyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[3-(3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-9-[3-(1-ethyl-3-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-ethyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-propyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(1-methylethyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-butyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(2-methylpropyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(3-methylbutyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-cyclopentyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(cyclopentylmethyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(2-cyclohexylethyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[4-(3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-9-[4-(1-ethyl-3-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[5-(3-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[5-(1-ethyl-3-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{5-[1-(1-methylethyl)-3-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[(1-propyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{[1-(1-methylethyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[(1-butyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{[1-(2-methylpropyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{[1-(3-methylbutyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[(1-cyclopentyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[(1-cyclohexyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-(4-piperidinylmethyl)-7,9-dihydro-8H-purin-8-one;-   6-amino-9-[(1-ethyl-4-piperidinyl)methyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-{[1-(1-methylethyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-propyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-butyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(2-methylpropyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(1-ethylpropyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(3-methylbutyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-cyclopentyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(cyclopentylmethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[2-(1-cyclohexyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{2-[1-(2-cyclohexylethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[2-(4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-9-[2-(1-ethyl-4-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-propyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(1-methylethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-butyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(2-methylpropyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(1-ethylpropyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(3-methylbutyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-cyclopentyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(cyclopentylmethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[3-(1-cyclohexyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{3-[1-(2-cyclohexylethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[3-(4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-9-[3-(1-ethyl-4-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-{3-[1-(1-methylethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-propyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(1-methylethyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-butyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(2-methylpropyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(1-ethylpropyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(3-methylbutyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-cyclopentyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(cyclopentylmethyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[4-(1-cyclohexyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{4-[1-(2-cyclohexylethyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-9-[4-(1-ethyl-4-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butylamino)-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butylamino)-9-[4-(1-ethyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[5-(4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[5-(1-ethyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[5-(1-propyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{5-[1-(1-methylethyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[5-(1-butyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{5-[1-(2-methylpropyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{5-[1-(3-methylbutyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[5-(1-cyclopentyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{5-[1-(cyclopentylmethyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{5-[1-(2-cyclohexylethyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[6-(4-piperidinyl)hexyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-[6-(1-ethyl-4-piperidinyl)hexyl]-7,9-dihydro-8H-purin-8-one;-   6-amino-2-(butyloxy)-9-{6-[1-(1-methylethyl)-4-piperidinyl]hexyl}-7,9-dihydro-8H-purin-8-one,    and;-   6-amino-2-[(1-methylethy)oxy]-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;    and salts thereof.

There is thus provided as a further aspect of the invention a compoundof formula (I), or a pharmaceutically acceptable salt thereof, for useas in therapy.

It will be appreciated that, when a compound of formula (I) or apharmaceutically acceptable salt thereof is used in therapy, it is usedas an active therapeutic agent.

There is also therefore provided a compound of formula (I), or apharmaceutically acceptable salt thereof, for use in the treatment ofallergic diseases and other inflammatory conditions, infectiousdiseases, and cancer.

There is also therefore provided a compound of formula (I), or apharmaceutically acceptable salt thereof, for use in the treatment ofallergic rhinitis.

There is also therefore provided a compound of formula (I), or apharmaceutically acceptable salt thereof, for use in the treatment ofasthma.

There is also therefore provided a vaccine adjuvant comprising acompound of formula (I), or a pharmaceutically acceptable salt thereof.

There is further provided an immugenic composition comprising an antigenor antigen composition and a compound of formula (I), or apharmaceutically acceptable salt thereof.

There is further provided a vaccine composition comprising an antigen orantigen composition and a compound of formula (I), or a pharmaceuticallyacceptable salt thereof.

There is further provided a method of treating or preventing diseasecomprising the administration to a human subject suffering from orsusceptible to disease, an immugenic composition comprising an antigenor antigen composition and a compound of formula (I), or apharmaceutically acceptable salt thereof.

There is further provided a method of treating or preventing diseasecomprising the administration to a patient human subject suffering fromor susceptible to disease, a vaccine composition comprising an antigenor antigen composition and a compound of formula (I), or apharmaceutically acceptable salt thereof.

There is further provided the use of a compound of formula (I), or apharmaceutically acceptable salt thereof, for the manufacture of animmugenic composition comprising an antigen or antigen composition, forthe treatment or prevention of disease.

There is further provided the use of a compound of formula (I), or apharmaceutically acceptable salt thereof, for the manufacture of avaccine composition comprising an antigen or antigen composition, forthe treatment or prevention of disease.

There is further provided the use of a compound of formula (I), or apharmaceutically acceptable salt thereof, for the manufacture of amedicament for the treatment of allergic diseases and other inflammatoryconditions, infectious diseases, and cancer.

There is further provided the use of a compound of formula (I), or apharmaceutically acceptable salt thereof, for the manufacture of amedicament for the treatment of allergic rhinitis.

There is further provided the use of a compound of formula (I), or apharmaceutically acceptable salt thereof, for the manufacture of amedicament for the treatment of asthma.

There is further provided a method of treatment of allergic diseases andother inflammatory conditions, infectious diseases, and cancer, whichmethod comprises administering to a human subject in need thereof atherapeutically effective amount of a compound of formula (I), or apharmaceutically acceptable salt thereof.

There is further provided a method of treatment of allergic rhinitis,which method comprises administering to a human subject in need thereofa therapeutically-effective amount of a compound of formula (I), or apharmaceutically acceptable salt thereof.

There is further provided a method of treatment of asthma, which methodcomprises administering to a human subject in need thereof atherapeutically effective amount of a compound of formula (I), or apharmaceutically acceptable salt thereof.

The invention provides in a further aspect, a combination comprising acompound of formula (I), or a pharmaceutically acceptable salt thereof,together with at least one other therapeutically active agent.

There is further provided a pharmaceutical composition comprising acompound of formula (I), or a pharmaceutically acceptable salt thereof,and one or more pharmaceutically acceptable diluents or carriers.

There is also provided a process for preparing a pharmaceuticalcomposition which comprises admixing a compound of formula (I), or apharmaceutically acceptable salt thereof, with one or morepharmaceutically acceptable diluents or carriers.

The compounds of formula (I) and salts thereof may be prepared by themethodology described herein, which constitutes a further aspect of thisinvention.

Accordingly, there is provided a process for the preparation of acompound of formula (I), which process comprises the deprotection of acompound of formula (II):

wherein R¹ and R² are as hereinbefore defined for a compound of formula(I) and R⁴ is C₁₋₆alkyl, and thereafter, if required, carrying out oneor more of the following optional steps:

-   (i). removing any necessary protecting group;-   (ii). preparing a salt of the compound so-formed.

There is further provided a process for the preparation of a compound offormula (I), which process comprises converting a compound of formula(I) to a further compound of formula (I) and thereafter, if required,carrying out one or more of the following optional steps:

-   (i). removing any necessary protecting group;-   (ii). preparing a salt of the compound so-formed.

In a further embodiment, a compound of formula (I) may also be preparedby deprotection of a compound of formula (IIP):

wherein R¹ is as hereinbefore defined for a compound of formula (I), R⁴is as hereinbefore defined for a compound of formula (II), and R^(2P) isa protected R² group wherein the protecting group is a suitableprotecting group, for example a tert-butoxycarbonyl group or acarbobenzyloxy group, and thereafter, if required, carrying out one ormore of the following optional steps:

-   (i). removing any necessary protecting group;-   (ii). preparing a salt of the compound so-formed.

The present invention covers all combinations of embodiments and aspectsherein described.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is described in terms known and appreciated bythose skilled in the art. For ease of reference certain termshereinafter are defined. The fact that certain terms are defined,however, should not be considered as indicative that defined terms areused in a manner inconsistent with the ordinary meaning or,alternatively, that any term that is undefined is indefinite or not usedwithin the ordinary and accepted meaning. Rather, all terms used hereinare believed to describe the invention such that one of ordinary skillcan appreciate the scope of the present invention. The followingdefinitions are meant to clarify, but not limit, the terms defined.

References to ‘alkyl’ include references to both straight-chain andbranched-chain aliphatic isomers of the corresponding alkyl containingup to eight carbon atoms, for example up to six carbon atoms, or up tofour carbon atoms, or up to two carbon atoms, or one carbon atom. Suchreferences to ‘alkyl’ are also applicable when an alkyl group is part ofanother group, for example an alkylamino or alkoxy group. Examples ofsuch alkyl groups and groups containing alkyl groups are C₁₋₈ alkyl,C₁₋₆alkyl, C₁₋₆alkylamino, and C₁₋₆alkoxy.

References to ‘cycloalkyl’ refer to monocyclic alkyl groups containingbetween three and seven carbon atoms, for example three carbon atoms, orfive carbon atoms, or six carbon atoms. Examples of such cycloalkylgroups are cyclopropyl, cyclopentyl, and cyclohexyl.

References to ‘heterocycle’ or ‘heterocyclyl’ refer to a monocyclicsaturated heterocyclic aliphatic ring containing 6 carbon atoms and oneheteroatom, which heteroatom is nitrogen. Such a heterocyclic ring ispiperidine or piperidinyl.

References to ‘halogen’ refer to iodine, bromine, chlorine or fluorine,typically bromine, chlorine, or fluorine. References to ‘halo’ refer toiodo, bromo, chloro or fluoro, typically bromo, chloro, or fluoro.

It is to be understood that references herein to compounds of theinvention mean a compound of formula (I) as the free base, or as a salt,for example a pharmaceutically acceptable salt.

Salts of the compounds of formula (I) include pharmaceuticallyacceptable salts and salts which may not be pharmaceutically acceptablebut may be useful in the preparation of compounds of formula (I) andpharmaceutically acceptable salts thereof. Salts may be derived fromcertain inorganic or organic acids, or certain inorganic or organicbases.

The invention includes within its scope all possible stoichiometric andnon-stoichiometric forms of the salts of the compounds of formula (I).

Examples of salts are pharmaceutically acceptable salts.Pharmaceutically acceptable salts include acid addition salts and baseaddition salts. For a review on suitable salts see Berge et al., J.Pharm. Sci., 66:1-19 (1977).

Examples of pharmaceutically acceptable acid addition salts of acompound of formula (I) include hydrobromide, hydrochloride, sulphate,p-toluenesulphonate, methanesulphonate, naphthalenesulphonate, andphenylsulphonate salts.

Examples of pharmaceutically acceptable base salts include alkali metalsalts such as those of sodium and potassium, and alkaline earth metalsalts such as those of calcium and magnesium.

Salts may be formed using techniques well-known in the art, for exampleby precipitation from solution followed by filtration, or by evaporationof the solvent.

Typically, a pharmaceutically acceptable acid addition salt can beformed by reaction of a compound of formula (I) with a suitable strongacid (such as hydrobromic, hydrochloric, sulphuric, p-toluenesulphonic,methanesulphonic or naphthalenesulphonic acids), optionally in asuitable solvent such as an organic solvent, to give the salt which isusually isolated for example by crystallisation and filtration.

It will be appreciated that many organic compounds can form complexeswith solvents in which they are reacted or from which they areprecipitated or crystallised. These complexes are known as “solvates”.For example, a complex with water is known as a “hydrate”. Solvents withhigh boiling points and/or solvents with a high propensity to formhydrogen bonds such as water, ethanol, iso-propyl alcohol, andN-methylpyrrolidinone may be used to form solvates. Methods for theidentification of solvated include, but are not limited to, NMR andmicroanalysis. Solvates of the compounds of formula (I) are within thescope of the invention. As used herein, the term solvate encompassessolvates of both a free base compound as well as any salt thereof.

Certain of the compounds of the invention may contain chiral atomsand/or multiple bonds, and hence may exist in one or more stereoisomericforms. The present invention encompasses all of the stereoisomers of thecompounds of the invention, including optical isomers, whether asindividual stereoisomers or as mixtures thereof including racemicmodifications. Any stereoisomer may contain less than 10% by weight, forexample less than 5% by weight, or less than 0.5% by weight, of anyother stereoisomer. For example, any optical isomer may contain lessthan 10% by weight, for example less than 5% by weight, or less than0.5% by weight, of its antipode.

Certain of the compounds of the invention may exist in tautomeric forms.It will be understood that the present invention encompasses all of thetautomers of the compounds of the invention whether as individualtautomers or as mixtures thereof.

The compounds of the invention may be in crystalline or amorphous form.Furthermore, some of the crystalline forms of the compounds of theinvention may exist as polymorphs, all of which are included within thescope of the present invention. The most thermodynamically stablepolymorphic form or forms of the compounds of the invention are ofparticular interest.

Polymorphic forms of compounds of the invention may be characterised anddifferentiated using a number of conventional analytical techniques,including, but not limited to, X-ray powder diffraction (XRPD), infraredspectroscopy (IR), Raman spectroscopy, differential scanning calorimetry(DSC), thermogravimetric analysis (TGA) and solid-state nuclear magneticresonance (ssNMR).

It will be appreciated from the foregoing that included within the scopeof the invention are solvates, hydrates, isomers and polymorphic formsof the compounds of formula (I) and salts thereof.

Examples of disease states in which the compounds of formula (I) andpharmaceutically acceptable salts thereof have potentially beneficialeffects include allergic diseases and other inflammatory conditions forexample allergic rhinitis and asthma, infectious diseases, and cancer.The compounds of formula (I) and pharmaceutically acceptable saltsthereof are also of potential use as vaccine adjuvants.

As modulators of the immune response the compounds of formula (I) andpharmaceutically acceptable salts thereof may also be useful, asstand-alone or in combination as an adjuvant, in the treatment and/orprevention of immune-mediated disorders, including but not limited toinflammatory or allergic diseases such as asthma, allergic rhinitis andrhinoconjuctivitis, food allergy, hypersensitivity lung diseases,eosinophilic pneumonitis, delayed-type hypersensitivity disorders,atherosclerosis, pancreatitis, gastritis, colitis, osteoarthritis,psoriasis, sarcoidosis, pulmonary fibrosis, respiratory distresssyndrome, bronchiolitis, chronic obstructive pulmonary disease,sinusitis, cystic fibrosis, actinic keratosis, skin dysplasia, chronicurticaria, eczema and all types of dermatitis.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may also be useful in the treatment and/or prevention ofreactions against respiratory infections, including but not limited toairways viral exacerbations and tonsillitis. The compounds may also beuseful in the treatment and/or prevention of autoimmune diseasesincluding but not limited to rheumatoid arthritis, psoriatic arthritis,systemic lupus erythematosus, Sjöegrens disease, ankylosing spondylitis,scleroderma, dermatomyositis, diabetes, graft rejection, includinggraft-versus-host disease, inflammatory bowel diseases including, butnot limited to, Crohn's disease and ulcerative colitis.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may also be useful in the treatment of infectious diseasesincluding, but not limited to, those caused by hepatitis viruses (e.g.hepatitis B virus, hepatitis C virus), human immunodeficiency virus,papillomaviruses, herpesviruses, respiratory viruses (e.g. influenzaviruses, respiratory syncytial virus, rhinovirus, metapneumovirus,parainfluenzavirus, SARS), and West Nile virus. The compounds of formula(I) and pharmaceutically acceptable salts thereof may also be useful inthe treatment of microbial infections caused by, for example, bacteria,fungi, or protozoa. These include, but are not limited to, tuberculosis,bacterial pneumonia, aspergillosis, histoplasmosis, candidosis,pneumocystosis, leprosy, chlamydia, cryptococcal disease,cryptosporidosis, toxoplasmosis, leishmania, malaria, andtrypanosomiasis.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may also be useful in the treatment of various cancers, inparticular the treatment of cancers that are known to be responsive toimmunotherapy and including, but not limited to, renal cell carcinoma,lung cancer, breast cancer, colorectal cancer, bladder cancer, melanoma,leukaemia, lymphomas and ovarian cancer.

It will be appreciated by those skilled in the art that referencesherein to treatment or therapy may, depending on the condition, extendto prophylaxis as well as the treatment of established conditions.

As mentioned herein, compounds of formula (I) and pharmaceuticallyacceptable salts thereof may be useful as therapeutic agents.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may be formulated for administration in any convenient way.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may, for example, be formulated for oral, topical, inhaled,intranasal, buccal, parenteral (for example intravenous, subcutaneous,intradermal, or intramuscular) or rectal administration. In one aspect,the compounds of formula (I) and pharmaceutically acceptable saltsthereof are formulated for oral administration. In a further aspect, thecompounds of formula (I) and pharmaceutically acceptable salts thereofare formulated for topical administration, for example intranasal orinhaled administration.

Tablets and capsules for oral administration may contain conventionalexcipients such as binding agents, for example syrup, acacia, gelatin,sorbitol, tragacanth, mucilage of starch, cellulose or polyvinylpyrrolidone; fillers, for example, lactose, microcrystalline cellulose,sugar, maize starch, calcium phosphate or sorbitol; lubricants, forexample, magnesium stearate, stearic acid, talc, polyethylene glycol orsilica; disintegrants, for example, potato starch, croscarmellose sodiumor sodium starch glycollate; or wetting agents such as sodium laurylsulphate. The tablets may be coated according to methods well known inthe art.

Oral liquid preparations may be in the form of, for example, aqueous oroily suspensions, solutions, emulsions, syrups or elixirs, or may bepresented as a dry product for constitution with water or other suitablevehicle before use. Such liquid preparations may contain conventionaladditives such as suspending agents, for example, sorbitol syrup, methylcellulose, glucose/sugar syrup, gelatin, hydroxymethyl cellulose,carboxymethyl cellulose, aluminium stearate gel or hydrogenated ediblefats; emulsifying agents, for example, lecithin, sorbitan mono-oleate oracacia; non-aqueous vehicles (which may include edible oils), forexample almond oil, fractionated coconut oil, oily esters, propyleneglycol or ethyl alcohol; or preservatives, for example, methyl or propylp-hydroxybenzoates or sorbic acid. The preparations may also containbuffer salts, flavouring, colouring and/or sweetening agents (e.g.mannitol) as appropriate.

Compositions for intranasal administration include aqueous compositionsadministered to the nose by drops or by pressurised pump. Suitablecompositions contain water as the diluent or carrier for this purpose.Compositions for administration to the lung or nose may contain one ormore excipients, for example one or more suspending agents, one or morepreservatives, one or more surfactants, one or more tonicity adjustingagents, one or more co-solvents, and may include components to controlthe pH of the composition, for example a buffer system. Further, thecompositions may contain other excipients such as antioxidants, forexample sodium metabisulphite, and taste-masking agents. Compositionsmay also be administered to the nose or other regions of the respiratorytract by nebulisation.

Intranasal compositions may permit the compound(s) of formula (I) or (a)pharmaceutically acceptable salt(s) thereof to be delivered to all areasof the nasal cavities (the target tissue) and further, may permit thecompound(s) of formula (I) or (a) pharmaceutically acceptable salt(s)thereof to remain in contact with the target tissue for longer periodsof time. A suitable dosing regime for intranasal compositions would befor the patient to inhale slowly through the nose subsequent to thenasal cavity being cleared. During inhalation the composition would beadministered to one nostril while the other is manually compressed. Thisprocedure would then be repeated for the other nostril. Typically, oneor two sprays per nostril would be administered by the above procedureone, two, or three times each day, ideally once daily. Of particularinterest are intranasal compositions suitable for once-dailyadministration.

The suspending agent(s), if included, will typically be present in anamount of from 0.1 to 5% (w/w), such as from 1.5% to 2.4% (w/w), basedon the total weight of the composition. Examples of pharmaceuticallyacceptable suspending agents include, but are not limited to, Avicel®(microcrystalline cellulose and carboxymethylcellulose sodium),carboxymethylcellulose sodium, veegum, tragacanth, bentonite,methylcellulose, xanthan gum, carbopol and polyethylene glycols.

Compositions for administration to the lung or nose may contain one ormore excipients may be protected from microbial or fungal contaminationand growth by inclusion of one or more preservatives. Examples ofpharmaceutically acceptable anti-microbial agents or preservativesinclude, but are not limited to, quaternary ammonium compounds (forexample benzalkonium chloride, benzethonium chloride, cetrimide,cetylpyridinium chloride, lauralkonium chloride and myristyl picoliniumchloride), mercurial agents (for example phenylmercuric nitrate,phenylmercuric acetate and thimerosal), alcoholic agents (for examplechlorobutanol, phenylethyl alcohol and benzyl alcohol), antibacterialesters (for example esters of para-hydroxybenzoic acid), chelatingagents such as disodium edetate (EDTA) and other anti-microbial agentssuch as chlorhexidine, chlorocresol, sorbic acid and its salts (such aspotassium sorbate) and polymyxin. Examples of pharmaceuticallyacceptable anti-fungal agents or preservatives include, but are notlimited to, sodium benzoate, sorbic acid, sodium propionate,methylparaben, ethylparaben, propylparaben and butylparaben. Thepreservative(s), if included, may be present in an amount of from 0.001to 1% (w/w), such as from 0.015% to 0.5% (w/w) based on the total weightof the composition.

Compositions (for example wherein at least one compound is insuspension) may include one or more surfactants which functions tofacilitate dissolution of the medicament particles in the aqueous phaseof the composition. For example, the amount of surfactant used is anamount which will not cause foaming during mixing. Examples ofpharmaceutically acceptable surfactants include fatty alcohols, estersand ethers, such as polyoxyethylene (20) sorbitan monooleate(Polysorbate 80), macrogol ethers, and poloxamers. The surfactant may bepresent in an amount of between about 0.01 to 10% (w/w), such as from0.01 to 0.75% (w/w), for example about 0.5% (w/w), based on the totalweight of the composition.

One or more tonicity-adjusting agent(s) may be included to achievetonicity with body fluids e.g. fluids of the nasal cavity, resulting inreduced levels of irritancy. Examples of pharmaceutically acceptabletonicity adjusting agents include, but are not limited to, sodiumchloride, dextrose, xylitol, calcium chloride, glucose, glycerine andsorbitol. A tonicity-adjusting agent, if present, may be included in anamount of from 0.1 to 10% (w/w), such as from 4.5 to 5.5% (w/w), forexample about 5.0% (w/w), based on the total weight of the composition.

The compositions of the invention may be buffered by the addition ofsuitable buffering agents such as sodium citrate, citric acid,trometamol, phosphates such as disodium phosphate (for example thedodecahydrate, heptahydrate, dihydrate and anhydrous forms), or sodiumphosphate and mixtures thereof.

A buffering agent, if present, may be included in an amount of from 0.1to 5% (w/w), for example 1 to 3% (w/w) based on the total weight of thecomposition.

Examples of taste-masking agents include sucralose, sucrose, saccharinor a salt thereof, fructose, dextrose, glycerol, corn syrup, aspartame,acesulfame-K, xylitol, sorbitol, erythritol, ammonium glycyrrhizinate,thaumatin, neotame, mannitol, menthol, eucalyptus oil, camphor, anatural flavouring agent, an artificial flavouring agent, andcombinations thereof.

One or more co-solvent(s) may be included to aid solubility of themedicament compound(s) and/or other excipients. Examples ofpharmaceutically acceptable co-solvents include, but are not limited to,propylene glycol, dipropylene glycol, ethylene glycol, glycerol,ethanol, polyethylene glycols (for example PEG300 or PEG400), andmethanol. In one embodiment, the co-solvent is propylene glycol.

Co-solvent(s), if present, may be included in an amount of from 0.05 to30% (w/w), such as from 1 to 25% (w/w), for example from 1 to 10% (w/w)based on the total weight of the composition.

Compositions for inhaled administration include aqueous, organic oraqueous/organic mixtures, dry powder or crystalline compositionsadministered to the respiratory tract by pressurised pump or inhaler,for example, reservoir dry powder inhalers, unit-dose dry powderinhalers, pre-metered multi-dose dry powder inhalers, nasal inhalers orpressurised aerosol inhalers, nebulisers or insufflators. Suitablecompositions contain water as the diluent or carrier for this purposeand may be provided with conventional excipients such as bufferingagents, tonicity modifying agents and the like. Aqueous compositions mayalso be administered to the nose and other regions of the respiratorytract by nebulisation. Such compositions may be aqueous solutions orsuspensions or aerosols delivered from pressurised packs, such as ametered dose inhaler, with the use of a suitable liquefied propellant.

Compositions for administration topically to the nose (for example, forthe treatment of rhinitis) or to the lung, include pressurised aerosolcompositions and aqueous compositions delivered to the nasal cavities bypressurised pump. Compositions which are non-pressurised and aresuitable for administration topically to the nasal cavity are ofparticular interest. Suitable compositions contain water as the diluentor carrier for this purpose. Aqueous compositions for administration tothe lung or nose may be provided with conventional excipients such asbuffering agents, tonicity-modifying agents and the like. Aqueouscompositions may also be administered to the nose by nebulisation.

A fluid dispenser may typically be used to deliver a fluid compositionto the nasal cavities. The fluid composition may be aqueous ornon-aqueous, but typically aqueous. Such a fluid dispenser may have adispensing nozzle or dispensing orifice through which a metered dose ofthe fluid composition is dispensed upon the application of auser-applied force to a pump mechanism of the fluid dispenser. Suchfluid dispensers are generally provided with a reservoir of multiplemetered doses of the fluid composition, the doses being dispensable uponsequential pump actuations. The dispensing nozzle or orifice may beconfigured for insertion into the nostrils of the user for spraydispensing of the fluid composition into the nasal cavity. A fluiddispenser of the aforementioned type is described and illustrated inInternational Patent Application publication number WO 2005/044354(Glaxo Group Limited). The dispenser has a housing which houses afluid-discharge device having a compression pump mounted on a containerfor containing a fluid composition. The housing has at least onefinger-operable side lever which is movable inwardly with respect to thehousing to move the container upwardly in the housing by means of a camto cause the pump to compress and pump a metered dose of the compositionout of a pump stem through a nasal nozzle of the housing. In oneembodiment, the fluid dispenser is of the general type illustrated inFIGS. 30-40 of WO 2005/044354.

Aqueous compositions containing a compound of formula (I) or apharmaceutically acceptable salt thereof may also be delivered by a pumpas disclosed in International Patent Application publication numberWO2007/138084 (Glaxo Group Limited), for example as disclosed withreference to FIGS. 22-46 thereof, or as disclosed in United Kingdompatent application number GB0723418.0 (Glaxo Group Limited), for exampleas disclosed with reference to FIGS. 7-32 thereof. The pump may beactuated by an actuator as disclosed in FIGS. 1-6 of GB0723418.0.

Dry powder compositions for topical delivery to the lung by inhalationmay, for example, be presented in capsules and cartridges of for examplegelatine, or blisters of for example laminated aluminium foil, for usein an inhaler or insufflator. Powder blend compositions generallycontain a powder mix for inhalation of the compound of formula (I) or apharmaceutically acceptable salt thereof and a suitable powder base(carrier/diluent/excipient substance) such as mono-, di-, orpolysaccharides (for example lactose or starch). Dry powder compositionsmay also include, in addition to the drug and carrier, a furtherexcipient (for example a ternary agent such as a sugar ester for examplecellobiose octaacetate, calcium stearate, or magnesium stearate.

In one embodiment, a composition suitable for inhaled administration maybe incorporated into a plurality of sealed dose containers provided onmedicament pack(s) mounted inside a suitable inhalation device. Thecontainers may be rupturable, peelable, or otherwise openableone-at-a-time and the doses of the dry powder composition administeredby inhalation on a mouthpiece of the inhalation device, as known in theart. The medicament pack may take a number of different forms, forinstance a disk-shape or an elongate strip. Representative inhalationdevices are the DISKHALER™ and DISKUS™ devices, marketed byGlaxoSmithKline.

A dry powder inhalable composition may also be provided as a bulkreservoir in an inhalation device, the device then being provided with ametering mechanism for metering a dose of the composition from thereservoir to an inhalation channel where the metered dose is able to beinhaled by a patient inhaling at a mouthpiece of the device. Exemplarymarketed devices of this type are TURBUHALER™ (AstraZeneca), TWISTHALER™(Schering) and CLICKHALER™ (Innovate.)

A further delivery method for a dry powder inhalable composition is formetered doses of the composition to be provided in capsules (one doseper capsule) which are then loaded into an inhalation device, typicallyby the patient on demand. The device has means to rupture, pierce orotherwise open the capsule so that the dose is able to be entrained intothe patient's lung when they inhale at the device mouthpiece. Asmarketed examples of such devices there may be mentioned ROTAHALER™(GlaxoSmithKline) and HANDIHALER™ (Boehringer Ingelheim.)

Pressurised aerosol compositions suitable for inhalation can be either asuspension or a solution and may contain a compound of formula (I) or apharmaceutically acceptable salt thereof and a suitable propellant suchas a fluorocarbon or hydrogen-containing chlorofluorocarbon or mixturesthereof, particularly hydrofluoroalkanes, especially1,1,1,2-tetrafluoroethane, 1,1,1,2,3,3,3-heptafluoro-n-propane or amixture thereof. The aerosol composition may optionally containadditional composition excipients well known in the art such assurfactants e.g. oleic acid, lecithin or an oligolactic acid orderivative thereof e.g. as described in WO 94/21229 and WO 98/34596(Minnesota Mining and Manufacturing Company) and co-solvents e.g.ethanol. Pressurised compositions will generally be retained in acanister (e.g. an aluminium canister) closed with a valve (e.g. ametering valve) and fitted into an actuator provided with a mouthpiece.

Ointments, creams and gels, may, for example, be formulated with anaqueous or oily base with the addition of suitable thickening and/orgelling agent and/or solvents. Such bases may thus, for example, includewater and/or an oil such as liquid paraffin or a vegetable oil such asarachis oil or castor oil, or a solvent such as polyethylene glycol.Thickening agents and gelling agents which may be used according to thenature of the base include soft paraffin, aluminium stearate,cetostearyl alcohol, polyethylene glycols, wool-fat, beeswax,carboxypolymethylene and cellulose derivatives, and/or glycerylmonostearate and/or non-ionic emulsifying agents.

Lotions may be formulated with an aqueous or oily base and will ingeneral also contain one or more emulsifying agents, stabilising agents,dispersing agents, suspending agents or thickening agents.

Powders for external application may be formed with the aid of anysuitable powder base, for example, talc, lactose or starch. Drops may beformulated with an aqueous or non-aqueous base also comprising one ormore dispersing agents, solubilising agents, suspending agents orpreservatives.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may, for example, be formulated for transdermal delivery bycomposition into patches or other devices (e.g. pressurised gas devices)which deliver the active component into the skin.

For buccal administration the compositions may take the form of tabletsor lozenges formulated in the conventional manner.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may also be formulated as suppositories, e.g. containingconventional suppository bases such as cocoa butter or other glycerides.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may also be formulated for parenteral administration by bolusinjection or continuous infusion and may be presented in unit dose form,for instance as ampoules, vials, small volume infusions or pre-filledsyringes, or in multidose containers with an added preservative. Thecompositions may take such forms as solutions, suspensions, or emulsionsin aqueous or non-aqueous vehicles, and may contain formulatory agentssuch as anti-oxidants, buffers, antimicrobial agents and/or tonicityadjusting agents. Alternatively, the active ingredient may be in powderform for constitution with a suitable vehicle, e.g. sterile,pyrogen-free water, before use. The dry solid presentation may beprepared by filling a sterile powder aseptically into individual sterilecontainers or by filling a sterile solution aseptically into eachcontainer and freeze-drying.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may also be formulated with vaccines as adjuvants to modulatetheir activity. Such compositions may contain antibody(ies) or antibodyfragment(s) or an antigenic component including but not limited toprotein, DNA, live or dead bacteria and/or viruses or virus-likeparticles, together with one or more components with adjuvant activityincluding but not limited to aluminium salts, oil and water emulsions,heat shock proteins, lipid A preparations and derivatives, glycolipids,other TLR agonists such as CpG DNA or similar agents, cytokines such asGM-CSF or IL-12 or similar agents.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may be employed alone or in combination with other therapeuticagents. The compounds of formula (I) and pharmaceutically acceptablesalts thereof and the other pharmaceutically active agent(s) may beadministered together or separately and, when administered separately,administration may occur simultaneously or sequentially, in any order.The amounts of the compound(s) of formula (I) or (a) pharmaceuticallyacceptable salt(s) thereof and the other pharmaceutically activeagent(s) and the relative timings of administration will be selected inorder to achieve the desired combined therapeutic effect. Theadministration of a combination of a compound of formula (I) or apharmaceutically acceptable salt thereof with other treatment agents maybe in combination by administration concomitantly in a unitarypharmaceutical composition including both compounds, or in separatepharmaceutical compositions each including one of the compounds.Alternatively, the combination may be administered separately in asequential manner wherein one treatment agent is administered first andthe other second or vice versa. Such sequential administration may beclose in time or remote in time.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may be used in combination with one or more agents useful in theprevention or treatment of viral infections. Examples of such agentsinclude, without limitation; polymerase inhibitors such as thosedisclosed in WO 2004/037818-A1, as well as those disclosed in WO2004/037818 and WO 2006/045613; JTK-003, JTK-019, NM-283, HCV-796,R-803, R1728, R1626, as well as those disclosed in WO 2006/018725, WO2004/074270, WO 2003/095441, US2005/0176701, WO 2006/020082, WO2005/080388, WO 2004/064925, WO 2004/065367, WO 2003/007945, WO02/04425, WO 2005/014543, WO 2003/000254, EP 1065213, WO 01/47883, WO2002/057287, WO 2002/057245 and similar agents; replication inhibitorssuch as acyclovir, famciclovir, ganciclovir, cidofovir, lamivudine andsimilar agents; protease inhibitors such as the HIV protease inhibitorssaquinavir, ritonavir, indinavir, nelfinavir, amprenavir, fosamprenavir,brecanavir, atazanavir, tipranavir, palinavir, lasinavir, and the HCVprotease inhibitors BILN2061, VX-950, SCH503034; and similar agents;nucleoside and nucleotide reverse transcriptase inhibitors such aszidovudine, didanosine, lamivudine, zalcitabine, abacavir, stavidine,adefovir, adefovir dipivoxil, fozivudine, todoxil, emtricitabine,alovudine, amdoxovir, elvucitabine, and similar agents; non-nucleosidereverse transcriptase inhibitors (including an agent havinganti-oxidation activity such as immunocal, oltipraz etc.) such asnevirapine, delavirdine, efavirenz, loviride, immunocal, oltipraz,capravirine, TMC-278, TMC-125, etravirine, and similar agents; entryinhibitors such as enfuvirtide (T-20), T-1249, PRO-542, PRO-140,TNX-355, BMS-806, 5-Helix and similar agents; integrase inhibitors suchas L-870,180 and similar agents; budding inhibitors such as PA-344 andPA-457, and similar agents; chemokine receptor inhibitors such asvicriviroc (Sch-C), Sch-D, TAK779, maraviroc (UK-427,857), TAK449, aswell as those disclosed in WO 02/74769, WO 2004/054974, WO 2004/055012,WO 2004/055010, WO 2004/055016, WO 2004/055011, and WO 2004/054581, andsimilar agents; neuraminidase inhibitors such as CS-8958, zanamivir,oseltamivir, peramivir and similar agents; ion channel blockers such asamantadine or rimantadine and similar agents; and interfering RNA andantisense oligonucleotides and such as ISIS-14803 and similar agents;antiviral agents of undetermined mechanism of action, for example thosedisclosed in WO 2005/105761, WO 2003/085375, WO 2006/122011, ribavirin,and similar agents. The compounds of formula (I) and pharmaceuticallyacceptable salts thereof may also be used in combination with one ormore other agents which may be useful in the prevention or treatment ofviral infections for example immune therapies (e.g. interferon or othercytokines/chemokines, cytokine/chemokine receptor modulators, cytokineagonists or antagonists and similar agents); and therapeutic vaccines,antifibrotic agents, anti-inflammatory agents such as corticosteroids ornon-steroidal anti-inflammatory agents (NSAIDs) and similar agents.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may be used in combination with one or more other agents whichmay be useful in the prevention or treatment of allergic disease,inflammatory disease, autoimmune disease, for example; antigenimmunotherapy, anti-histamines, steroids, NSAIDs, bronchodilators (e.g.beta 2 agonists, adrenergic agonists, anticholinergic agents,theophylline), methotrexate, leukotriene modulators and similar agents;monoclonal antibody therapy such as anti-IgE, anti-TNF, anti-IL-5,anti-IL-6, anti-IL-12, anti-IL-1 and similar agents; receptor therapiese.g. entanercept and similar agents; antigen non-specificimmunotherapies (e.g. interferon or other cytokines/chemokines,cytokine/chemokine receptor modulators, cytokine agonists orantagonists, TLR agonists and similar agents).

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may be used in combination with one or more other agents whichmay be useful in the prevention or treatment of cancer, for examplechemotherapeutics such as alkylating agents, topoisomerase inhibitors,antimetabolites, antimitotic agents, kinase inhibitors and similaragents; monoclonal antibody therapy such as trastuzumab, gemtuzumab andother similar agents; and hormone therapy such as tamoxifen, goserelinand similar agents.

The pharmaceutical compositions according to the invention may also beused alone or in combination with at least one other therapeutic agentin other therapeutic areas, for example gastrointestinal disease. Thecompositions according to the invention may also be used in combinationwith gene replacement therapy.

The invention includes in a further aspect a combination comprising acompound of formula (I), or a pharmaceutically acceptable salt thereof,together with at least one other therapeutically active agent.

The combinations referred to above may conveniently be presented for usein the form of a pharmaceutical composition and thus pharmaceuticalcompositions comprising a combination as defined above together with atleast one pharmaceutically acceptable diluent or carrier thereofrepresent a further aspect of the invention.

A therapeutically effective amount of a compound of formula (I) or apharmaceutically acceptable salt thereof will depend upon a number offactors. For example, the species, age, and weight of the recipient, theprecise condition requiring treatment and its severity, the nature ofthe composition, and the route of administration are all factors to beconsidered. The therapeutically effective amount ultimately should be atthe discretion of the attendant physician. Regardless, an effectiveamount of a compound of the present invention for the treatment ofhumans suffering from frailty, generally, should be in the range of0.0001 to 100 mg/kg body weight of recipient per day. More usually theeffective amount should be in the range of 0.001 to 10 mg/kg body weightper day. Thus, for a 70 kg adult one example of an actual amount per daywould usually be from 7 to 700 mg. For intranasal and inhaled routes ofadministration, typical doses for a 70 kg adult should be in the rangeof 1 microgramme to 1 mg per day. This amount may be given in a singledose per day or in a number (such as two, three, four, five, or more) ofsub-doses per day such that the total daily dose is the same. Aneffective amount of a pharmaceutically acceptable salt of a compound offormula (I) may be determined as a proportion of the effective amount ofthe compound of formula (I) or a pharmaceutically acceptable saltthereof per se. Similar dosages should be appropriate for treatment ofthe other conditions referred to herein.

Compounds of formula (I) and pharmaceutically acceptable salts thereofmay also be administered at any appropriate frequency e.g. 1-7 times perweek. The precise dosing regimen will of course depend on factors suchas the therapeutic indication, the age and condition of the patient, andthe particular route of administration chosen.

Pharmaceutical compositions may be presented in unit-dose formscontaining a predetermined amount of active ingredient per unit dose.Such a unit may contain, as a non-limiting example, 0.5 mg to 1 g of acompound of formula (I) or a pharmaceutically acceptable salt thereof,depending on the condition being treated, the route of administration,and the age, weight, and condition of the patient. Preferred unit-dosagecompositions are those containing a daily dose or sub-dose, as hereinabove recited, or an appropriate fraction thereof, of an activeingredient. Such pharmaceutical compositions may be prepared by any ofthe methods well-known in the pharmacy art.

There is thus further provided a pharmaceutical composition comprising acompound of formula (I), or a pharmaceutically acceptable salt thereof,and one or more pharmaceutically acceptable diluents or carriers.

There is also provided a process for preparing such a pharmaceuticalcomposition which comprises admixing a compound of formula (I), or apharmaceutically acceptable salt thereof, with one or morepharmaceutically acceptable diluents or carriers.

Throughout the description and the claims which follow, unless thecontext requires otherwise, the word ‘comprise’, and variations such as‘comprises’ and ‘comprising’, will be understood to imply the inclusionof a stated integer or step or group of integers but not to theexclusion of any other integer or step or group of integers or steps.

The compounds of formula (I) and salts thereof may be prepared by themethodology described herein, which constitutes a further aspect of thisinvention.

Accordingly, there is provided a process for the preparation of acompound of formula (I), which process comprises the deprotection of acompound of formula (II):

wherein R¹ and R² are as hereinbefore defined for a compound of formula(I) and R⁴ is C₁₋₆alkyl, and thereafter, if required, carrying out oneor more of the following optional steps:

-   (i). removing any necessary protecting group;-   (ii). preparing a salt of the compound so-formed.

There is further provided a process for the preparation of a compound offormula (I), which process comprises converting a compound of formula(I) to a further compound of formula (I) and thereafter, if required,carrying out one or more of the following optional steps:

-   (i). removing any necessary protecting group;-   (ii). preparing a salt of the compound so-formed.

For example, a compound of formula (II) is dissolved in a suitablesolvent, for example methanol, and treated with 4N solution of hydrogenchloride in a suitable solvent, for example 1,4-dioxane. The reaction isstirred at a suitable temperature, for example room temperature, for asuitable period of time, for example 4-6 hours, and the solvent removedunder reduced pressure to give a material that is then suspended inwater. A suitable aqueous base, for example 1M aqueous potassiumcarbonate solution, is added and the resultant solid is then filteredand washed with water before being dried to give a compound of formula(I). Alternatively, after removal of the solvent under reduced pressure,the material may be dissolved in a suitable solvent, for examplemethanol, and eluted through a suitable ion-exchange column, for examplean aminopropyl SPE column, and the solvent removed under reducedpressure to give a compound of formula (I).

A compound of formula (I) may also be prepared by deprotection of acompound of formula (IIP):

wherein R¹ is as hereinbefore defined for a compound of formula (I), R⁴is as hereinbefore defined for a compound of formula (II), and R^(2P) isa protected R² group wherein the protecting group is a suitableprotecting group, for example a tert-butoxycarbonyl group or acarbobenzyloxy group, and thereafter, if required, carrying out one ormore of the following optional steps:

-   (i). removing any necessary protecting group;-   (ii). preparing a salt of the compound so-formed.

For example, a solution of 4N hydrogen chloride in dioxane is added to asolution of a compound of formula (IIP) in a suitable solvent, forexample methanol. After a suitable period of time, for example 4-5 hoursat a suitable temperature, for example ambient temperature, the reactionmixture is concentrated and dried under high vacuum. The crude productis then purified by, for example, chromatography.

A compound of formula (II) may be prepared by reaction of a compound offormula (III):

wherein R¹ is as hereinbefore defined for a compound of formula (I) andR⁴ is as hereinbefore defined for a compound of formula (II), with acompound of formula (X):

R²—OH  (X)

wherein R² is as defined for a compound of formula (I) under Mitsonobuconditions in the presence of suitable reaction mediators such as1,1-(azodicarbonyl)dipiperidine and tributylphosphine.

For example, a compound of formula (III), a compound of formula (X), andtributylphosphine are dissolved in a suitable solvent, for exampletetrahydrofuran. 1,1′-(Azodicarbonyl)dipiperidine is added and thereaction mixture stirred at a suitable temperature, for example ambienttemperature, for a suitable period of time, for example 12-18 hours. Thesolvent is removed under reduced pressure and the residue purified by,for example column chromatography.

A compound of formula (II) may also be prepared by reaction of acompound of formula (III), for example a salt of a compound of formula(III) such as the trifluoroacetate salt, with a compound of formula(XI):

R²-L  (XI)

wherein R² is as hereinbefore defined for a compound of formula (I) andL is a suitable leaving group, for example a halogen atom, for example abromine atom.

For example, a mixture of the trifluoroacetate salt of a compound offormula (III) and a suitable base, for example potassium carbonate, in asuitable dry solvent, for example dry N,N-dimethylformamide is heatedwith stirring at a suitable temperature, for example 55-65° C. for asuitable period of time, for example 1-1.5 hours. A compound of formula(XI) is added and the stirring mixture heated at a suitable temperature,for example, 45-55° C. for a suitable period of time, for example2.5-3.5 hours. The temperature of the reaction mixture is reduced to asuitable temperature, for example ambient temperature, and the stirringcontinued for a suitable period of time, for example 15-72 hours. Thereaction mixture is then heated to a suitable temperature, for example50-60° C., and reaction continued for a further 3-6 hours. Water is thenadded and the mixture extracted with a suitable solvent, for exampleethyl acetate. The combined extracts are washed with water, then brine,and dried, for example by passing through a phase separation cartridge,and the solvent removed under reduced pressure. This crude product ispurified by, for example reversed-phase chromatography. The remainingaqueous mixture is made basic with a suitable base, for examplesaturated aqueous sodium hydrogen carbonate solution, extracted with asuitable solvent, for example dichloromethane, and the combined extractsdried, for example by passing through a phase separation cartridge, andthe solvent removed.

A compound of formula (II), wherein the R³ group as defined for acompound of formula (I) is C₁₋₈alkyl or C₃₋₇cycloalkylC₀₋₆alkyl, may beprepared by reaction of a compound of formula (II), wherein the R³ groupas defined for a compound of formula (I) is hydrogen, with a compound offormula (XIX):

R³-X  (XIX)

wherein R³ is C₁₋₈alkyl, or C₃₋₇cycloalkylC₀₋₆alkyl and X is a suitableleaving group, for example a halo group such as an iodo group.

For example, a compound of formula (II), wherein the R³ group as definedfor a compound of formula (I) is hydrogen, is suspended in a suitablesolvent, for example DMF, and heated briefly, for example with a heatgun to give a solution. To this is added a compound of formula (XIX) ina suitable solvent, for example DMF, and a suitable base, for exampleDIPEA added. The reaction is stirred at a suitable temperature, forexample ambient temperature, overnight. Further compound of formula(XIX) may be added and stirring continued for a further period of time,for example 18-30 hours, then further compound of formula (XIX) may beadded and stirring continued for a suitable period of time, for example72 hours. The solvent is then removed under, for example, a stream ofnitrogen, to give a compound of formula (II), wherein the R³ group asdefined for a compound of formula (I) is C₁₋₈alkyl orC₃₋₇cycloalkylC₀₋₆alkyl.

A compound of formula (II), wherein the R³ group as defined for acompound of formula (I) is hydrogen, may be prepared by reduction, forexample hydrogenation, of a compound of formula (IIP) as hereinbeforedefined.

For example, a compound of formula (IIP) in a suitable solvent, forexample ethanol, is hydrogenated over 10% palladium on carbon at asuitable temperature, for example ambient temperature, for a suitableperiod of time, for example 12-18 hours. The mixture is then filtered,for example through Celite, under a suitable atmosphere, for example anatmosphere of nitrogen, washed with a suitable solvent, for exampleethanol, and the solvent removed by evaporation in vacuo to give acompound of formula (II), wherein the R³ group as defined for a compoundof formula (I) is hydrogen.

A compound of formula (IIP) may be prepared by reaction of a compound offormula (III), for example a salt of a compound of formula (III) such asthe trifluoroacetate salt, with a compound of formula (XII):

R^(2P)—U  (XII)

wherein R^(2P) is as hereinbefore defined for a compound of formula(IIP) and U is a suitable leaving group, for example a halogen atom, forexample a bromine atom.

For example, a suitable base, for example potassium carbonate, is addedto a solution of the trifluoroacetate salt of a compound of formula(III) in a suitable dry solvent, for example dry N,N-dimethylformamide,and the reaction mixture heated at a suitable temperature, for example55-65° C. for a suitable period of time, for example 1-1.5 hours. Acompound of formula (XII) is added using additional dry solvent toensure complete transfer of the compound of formula (XII), and thereaction mixture stirred at a suitable temperature, for example 50-60°C. for a suitable period of time, for example 3-4 hours. The temperatureof the reaction mixture is then reduced to a suitable temperature, forexample ambient temperature, and stirring is continued for a suitableperiod of time, for example 15-24 hours. The reaction mixture is thenheated to a suitable temperature, for example at 45-55° C. and stirringis continued for a further 4.5-5.5 hours. Water is added and thereaction mixture extracted with a suitable solvent, for example ethylacetate. The combined organic extracts are washed with water, dried, forexample over anhydrous sodium sulphate, filtered, concentrated and driedunder reduced pressure. The crude product is then purified, for exampleby chromatography.

A compound of formula (III) may be prepared from the a salt of acompound of formula (III), for example the trifluoroacetate salt, bypassing a solution of the salt of a compound of formula (III) through anion-exchange column.

For example, the trifluoroacetate salt of a compound of formula (III) isdissolved in a suitable solvent, for example a mixture of methanol anddichloromethane, and loaded onto a preconditioned aminopropyl SPEcartridge. The cartridge is eluted with a mixture of methanol anddichloromethane, and the solvent removed under reduced pressure to givea compound of formula (III).

A salt of a compound of formula (III) may be prepared by deprotection ofa compound of formula (IV):

wherein R¹ is as hereinbefore defined for a compound of formula (I), R⁴is as hereinbefore defined for a compound of formula (II), and P is aprotecting group, for example a tetrahydro-2H-pyran-2-yl group, in thepresence of a suitable acid, for example trifluoroacetic acid.

For example, a suitable acid, for example trifluoroacetic acid, is addedto a solution of a compound of formula (IV) in a suitable solvent, forexample methanol. The mixture is stirred at a suitable temperature, forexample ambient temperature, for a suitable period of time, for example48-72 hours, to give a suspension. The reaction mixture is thenconcentrated under reduced pressure before being diluted with a suitablesolvent, for example ethyl acetate. The resultant mixture is filteredand washed with a small volume of a suitable solvent, for example ethylacetate until the filtrate is colourless. The residue is dried in airand then under reduced pressure to give the salt of a compound offormula (III). The filtrate may be concentrated and the concentratediluted with a small volume of a suitable solvent, for example ethylacetate, and then filtered and dried to yield a second crop of the saltof a compound of formula (III).

A compound of formula (III), for example a salt of a compound of formula(III) such as the trifluoroacetate salt, may also be prepared byreaction of a compound of formula (VI):

wherein R¹ is as hereinbefore defined for a compound of formula (I) andP is as hereinbefore defined for a compound of formula (IV), with asuitable halogenating agent, for example N-bromosuccinimide, followed byreaction with an alkoxide anion, for example a methoxide anion, and thenisolated in the presence of a suitable acid, for example trifluoroaceticacid.

For example, to a solution of crude compound of formula (VI) in asuitable dry solvent, for example dry chloroform, at a suitabletemperature, for example ambient temperature, is added a suitablehalogenating agent, for example N-bromosuccinimide, in portions over asuitable period of time, for example 5 minutes. The solution is stirredat a suitable temperature, for example ambient temperature, for asuitable period of time, for example 25-35 minutes. The reaction mixtureis then washed with water and the organic phase dried by, for example,passing through a hydrophobic frit and concentrated under reducedpressure. The resultant solid is dissolved in a suitable dry solvent,for example dry methanol, and a suitable alkoxide, for example asolution of sodium methoxide in methanol, is added at a suitabletemperature, for example ambient temperature, under an inert atmosphere,for example an atmosphere of nitrogen. The reaction mixture is heated ata suitable temperature, for example 60-70° C., with a condenserattached, for a suitable period of time, for example 12-18 hours. Thereaction mixture is then cooled and concentrated under reduced pressure.The residue is then taken up in a suitable solvent, for example ethylacetate, and poured into a suitable aqueous medium, for examplesaturated aqueous ammonium chloride solution. The organic layer isseparated and washed further with water, dried, for example overmagnesium sulphate, filtered and concentrated under reduced pressure. Toa solution of this material in a suitable dry solvent, such as drymethanol, at a suitable temperature, for example ambient temperature, isadded a suitable acid, for example trifluoroacetic acid. The reaction isstirred for a suitable period of time, for example 25-35 hours, andconcentrated under reduced pressure.

A compound of formula (IV) may be prepared by reaction of a compound offormula (V):

wherein R¹ is as hereinbefore defined for a compound of formula (I), Pis as hereinbefore defined for a compound of formula (IV), and Q is ahalogen atom, for example a bromine atom, with an alkoxide anion, forexample methoxide anion.

For example, a solution of a compound of formula (V) in a suitablesolvent, for example methanol, is heated to reflux with a solution of asuitable alkoxide, for example sodium methoxide, in a suitable solvent,for example methanol, for a suitable period of time, for example 4-5hours. The reaction mixture is concentrated under reduced pressure andpartitioned between a suitable organic solvent, for example ethylacetate, and a suitable aqueous medium, for example saturated aqueousammonium chloride solution. The organic phase is separated, washed, forexample with brine, and dried by, for example passing through ahydrophobic frit. The solvent is then removed under reduced pressure.

A compound of formula (V) may be prepared by reaction of a compound offormula (VI) with a suitable halogenating agent, such asN-bromosuccinimide.

For example, a compound of formula (VI) is dissolved in a suitablesolvent, for example chloroform, and cooled to a suitable temperature,for example 0-0.5° C. To this solution is added a suitable halogenatingagent, such as N-bromosuccinimide, while maintaining the temperaturebelow about 3° C. The solution is stirred at a suitable temperature, forexample 2-3° C. for a suitable period of time, for example 30-45 minutesthen allowed to warm to a suitable temperature, for example ambienttemperature, and stirred for a suitable period of time, for example 5-7hours. The reaction mixture is then washed with water and the organicphase dried and separated from the aqueous phase using, for example, ahydrophobic frit. The organic solvent is then removed and the crudeproduct purified by, for example, chromatography.

A compound of formula (VI) wherein R¹ is C₁₋₆alkoxy may be prepared byreaction of a compound of formula (VII):

wherein P is as hereinbefore defined for a compound of formula (IV), andT is a suitable leaving group, for example a halogen atom, for example achlorine atom or a fluorine atom, with a solution of a compound offormula (XIII):

R¹-M  (XIII)

wherein R¹ is C₁₋₆alkoxy and M is a suitable alkali metal ligand such assodium, prepared in a solvent of formula (XIIIS):

R¹—H  (XIIIS)

wherein the R¹ group in the compound of formula (XIII) is the same asthe R¹ group in the solvent of formula (XIIIS).

For example, a compound of formula (XIII) such as sodium t-butoxide, isadded to a solvent of formula (XIIIS). The mixture is stirred untilhomogeneous, then a compound of formula (VII) is added. The reactionmixture is heated to a suitable temperature, for example 100° C., for asuitable period of time, for example 12-18 hours. The solvent issubstantially removed under reduced pressure and partitioned between asuitable solvent, for example diethyl ether, and water. The organicphase is separated and the aqueous phase re-extracted with furthersolvent. The organic layers are then isolated, combined, dried using asuitable drying agent, for example anhydrous magnesium sulphate. Thedrying agent is removed by filtration and the solvent removed from theproduct under reduced pressure.

A compound of formula (VI) wherein R¹ is C₁₋₆alkylamino may be preparedby reaction of a compound of formula (VII) with a compound of formula(XIV):

R¹—H  (XIV)

wherein R¹ is C₁₋₆alkylamino.

For example, a compound of formula (XIV) is added to a solution of acompound of formula (VII) in a suitable dry solvent, for example dryethylene glycol, at a suitable temperature, for example ambienttemperature, under a suitable inert atmosphere, for example anatmosphere of nitrogen. The reaction mixture is heated at a suitabletemperature, for example 110-130° C., for a suitable period of time, forexample 12-18 hours. The reaction is then cooled to a suitabletemperature, for example ambient temperature, diluted with a suitablesolvent, for example ethyl acetate, and washed with water. The organiclayer is dried with a suitable drying agent, for example anhydrousmagnesium sulphate, filtered and concentrated under reduced pressure toyield a compound of formula (VI) wherein R¹ is C₁₋₆alkylamino.

A compound of formula (VII) may be prepared by reaction of a compound offormula (VIII):

wherein P is as hereinbefore defined for a compound of formula (IV), andT is as hereinbefore defined for a compound of formula (VII), and V is asuitable leaving group, for example a halogen atom, for example achlorine atom, with an alcoholic solution of ammonia, for example asolution of ammonia in iso-propyl alcohol.

For example, a compound of formula (VIII) is heated with an alcoholicsolution of ammonia, for example a 2M solution of ammonia in iso-propylalcohol, at a suitable temperature, for example 50-60° C., for asuitable period of time, for example 5-6 hours. The reaction mixture isthen left to stand at a suitable temperature, for example ambienttemperature, for a suitable period of time, for example 12-18 hours. Afurther quantity of the alcoholic solution of ammonia, for example a 2Msolution of ammonia in iso-propyl alcohol, is added to break up theresultant cake and the reaction mixture heated for a further period oftime, for example 8-10 hours, until the reaction is complete. Water isadded to the reaction mixture and the solid removed by filtration,washed with a suitable washing medium, for example a mixture ofiso-propyl alcohol and water, and then dried, for example by air-dryingunder suction to give a first crop of a compound of formula (VII). Thefiltrate is allowed to stand for a further period of time, for example12-18 hours and the resultant second crop of a compound of formula (VII)isolated by filtration and dried.

A compound of formula (VII) may also be prepared by reaction of acompound of formula (IX):

wherein T is as hereinbefore defined for a compound of formula (VII),and V is as hereinbefore defined for a compound of formula (VIII), witha compound of formula (XV):

P^(U)—H  (XV)

wherein P^(U) is a suitable precursor to the protecting group P, forexample a 3,4-dihydro-2H-pyranyl group, followed by reaction with analcoholic solution of ammonia, for example a solution of ammonia iniso-propyl alcohol.

For example, p-toluenesulfonic acid monohydrate is added to a solutionof a compound of formula (IX) in a suitable dry solvent, for example dryethyl acetate. The reaction mixture is heated to a suitable temperature,for example 50-60° C., and a compound of formula (XV) added. Thereaction is stirred at a suitable temperature, for example 50-60° C.,for a suitable period of time, for example 1-2 hours, and the solventremoved under reduced pressure. A suspension of the resultant solid inan alcoholic solution of ammonia, for example a 2M solution of ammoniain iso-propyl alcohol is heated under a suitable inert atmosphere, forexample an atmosphere of nitrogen, at a suitable temperature, forexample 60-70° C., for a suitable period of time, for example 4-5 hourswith an attached condenser. The reaction mixture is poured into waterand allowed to cool for a suitable period of time, for example 12-18hours. The resultant precipitate is isolated by filtration and dried.

A compound of formula (VII) may also be prepared by reaction of acompound of formula (IXA):

wherein T is a fluorine atom, with a suitable protecting agent, forexample a silylating agent such as N,O-bis(trimethylsilyl)acetamide,followed by reaction of the protected compound of formula (IXA) with acompound of formula (XVE):

P^(U)-E  (XVE)

wherein P^(u) is a suitable precursor to the protecting group P, forexample a 3,4-dihydro-2H-pyranyl group and E is an acyloxy group, forexample an acetate group.

For example, a suitable protecting agent, for exampleN,O-bis(trimethylsilyl)acetamide, is added to a stirred suspension of acompound of formula (IXA) in a suitable anhydrous solvent, for exampleanhydrous acetonitrile, and the resulting mixture heated to reflux andmaintained at that temperature for a suitable period of time, forexample 2-4 hours. The reaction mixture is then cooled to a suitabletemperature, for example 0-5° C. A solution of a compound of formula(XVE) in a suitable anhydrous solvent, for example anhydrousacetonitrile is then added slowly via a dropping funnel followed by thedropwise addition of a Lewis acid, for example trimethylsilyltrifluoromethanesulfonate. The reaction mixture is heated to a suitabletemperature, for example 8-12° C. and stirring maintained for a suitableperiod of time, for example 1-2 hours. The mixture is then quenched byaddition of 1M sodium carbonate. The organic layer is cooled to 0° C.with stirring. The precipitated solid is then collected by, for example,filtration and dried.

A compound of formula (VIII) may be prepared by reaction of a compoundof formula (IX) with a compound of formula (XV).

For example, to a compound of formula (IX) is added a suitable organicsolvent, for example ethyl acetate, followed by p-toluenesulfonic acid.The mixture is heated to a suitable temperature, for example 50-60° C.and then a compound of formula (XV) added. The reaction mixture is thenheated at a suitable temperature, for example 50-60° C. for a suitableperiod of time, for example 4-5 hours. The solvent is then removed fromthe reaction mixture under reduced pressure to yield a compound offormula (VIII).

A compound of formula (X) wherein the R³ is C₁₋₈alkyl and the R³ groupis attached to the nitrogen atom of the heterocycle, may be prepared byreaction of a compound of formula (X), wherein the R³ group is ahydrogen atom, with a compound of formula (XVI):

R³—W  (XVI)

wherein W is a leaving group, for example a halogen atom, for example aniodine atom.

For example, to a stirring solution of a compound of formula (X) and asuitable base, for example potassium carbonate, in a suitable drysolvent, for example dry N,N-dimethylformamide, is added a compound offormula (XVI). The reaction mixture is then stirred at a suitabletemperature, for example ambient temperature, for a suitable period oftime, for example 10-15 hours. The solvent is partially removed underreduced pressure and the residue partitioned between water and asuitable organic solvent, for example ethyl acetate. The aqueous layeris washed with further organic solvent, and the combined organic phaseis dried, for example using a hydrophobic frit, and concentrated underreduced pressure to yield a compound of formula (X) wherein R³ isC₁₋₈alkyl and R³ is attached to the nitrogen atom of the heterocycle.

Alternatively, to stirring solution of a salt of a compound of formula(X), for example the hydrochloride salt, and a suitable base, forexample potassium carbonate, in a suitable dry solvent, for example dryacetonitrile, is added a compound of formula (XVI). The reaction mixtureis then stirred at a suitable temperature, for example ambienttemperature, for a suitable period of time, for example 3-6 hours. Thesolvent is partially removed under reduced pressure and the residuepartitioned between water and a suitable organic solvent, for exampleethyl acetate. The aqueous layer is washed with further organic solvent,and the combined organic phase is dried, for example using a hydrophobicfrit, and concentrated under reduced pressure to yield a compound offormula (X) wherein R³ is C₁₋₈alkyl and R³ is attached to the nitrogenatom of the heterocycle.

Alternatively, to a stirring mixture of a compound of formula (X) and asuitable base, for example potassium carbonate in a suitable drysolvent, for example dry N,N-dimethylformamide, is added a compound offormula (XVI). The reaction mixture becomes warm, and is cooled toambient temperature using, for example using a cold water bath. After asuitable period of time, for example 1-3 hours, the solvent is removedunder reduced pressure, the residue treated with water and extractedthree times with a suitable organic solvent, for example ethyl acetate.The combined organic extracts are washed with water then brine, driedfor example by passing through a phase separation cartridge, and thesolvent removed under reduced pressure to yield a compound of formula(X) wherein R³ is C₁₋₈alkyl and R³ is attached to the nitrogen atom ofthe heterocycle.

A compound of formula (XI) wherein R³ is C₁₋₈alkyl and R³ is attached tothe nitrogen atom of the heterocycle, may be prepared by reaction of acompound of formula (X) wherein R³ is C₁₋₈alkyl and R³ is attached tothe nitrogen atom of the heterocycle with a compound of formula (XVII):

H—X  (XVII)

wherein X is a halogen atom, for example a bromine atom.

For example, a 48% aqueous solution of a compound of formula (XVII) isadded to a compound of formula (X) wherein R³ is C₁₋₈alkyl and R³ isattached to the nitrogen atom of the heterocycle and the stirringmixture heated at reflux for a suitable period of time, for example 5-7hours. After cooling, the solvent is removed under reduced pressure, theresidue treated with water, and made basic by addition of a suitablebase, for example 1M aqueous potassium carbonate solution. The mixtureis shaken with a suitable organic solvent, for example dichloromethane,filtered to remove unwanted solid, and the filtrate separated. Theaqueous layer is further extracted with organic solvent and the combinedextracts washed with dilute brine, dried by, for example, passingthrough a phase separation cartridge, and the solvent removed underreduced pressure.

A compound of formula (XII) may be prepared by reaction of a compound offormula (XVIII):

R^(2P)—OH  (XVIII)

wherein R^(2P) is as hereinbefore defined for a compound of formula(IIP), with tetrabromomethane.

For example, tetrabromomethane is added to a solution of a compound offormula (XVIII) in a suitable organic solvent, for example methylenechloride. The reaction mixture is cooled to a suitable temperature, forexample 0° C., and a solution of triphenylphosphine in a suitableorganic solvent, for example methylene chloride is added. After asuitable period if time, for example 0.5-2 hours at a suitabletemperature, for example 0° C., the reaction mixture is concentratedunder reduced pressure and purified, for example by chromatography.

Abbreviations

The following list provides definitions of certain abbreviations as usedherein. It will be appreciated that the list is not exhaustive, but themeaning of those abbreviations not herein below defined will be readilyapparent to those skilled in the art.

-   DCM Dichloromethane-   DME 1,2-Dimethoxyethane-   DMF N,N-Dimethylformamide-   EtOAc Ethyl acetate-   Et₂O Diethyl ether-   h hours-   HCl Hydrochloric acid-   HPLC High performance liquid chromatography-   ISCO Companion Automated flash chromatography equipment with    fraction analysis by UV absorption available from Presearch Limited,    Basingstoke, Hants., RG24 8PZ, UK-   MDAP HPLC Reverse phase HPLC on a C₁₈ column using a two-solvent    gradient elution with (A) water containing formic acid (0.1%)    and (B) acetonitrile-water (95:5 v/v) containing formic acid (0.05%)    as the eluents, and analysis of the fractions by electrospray mass    spectroscopy.-   MeOH Methanol-   mins minutes-   NBS N-Bromosuccinimide-   Stripped Removal of solvent under reduced pressure-   TBME Tertiary butyl methyl ether-   TFA Trifluoroacetic acid-   iPr iso-Propyl-   t-Bu tert-Butyl-   Ms Mesyl-   Ac Acetyl-   n-Bu n-Butyl-   Ph Phenyl-   rt room temperature

The synthetic processes hereinbefore described are summarised in Scheme1.

Typical reaction conditions for each of the synthetic steps of Scheme 1are provided below:

-   A Dihydropyran/paratoluene sulphonic acid, e.g. 50° C. for 3-6    hours.-   A1 Dihydropyran/paratoluene sulphonic acid, e.g. 50° C. for 1 hour,    then ammonia/iPrOH, e.g. 60° C. for 4 hours, then add water and cool    to ambient temperature over 12-18 hours.-   A2 BSA in MeCN, reflux, cool to 0° C., then THP acetate in MeCN,    warm to 10° C., then NaHCO₃ (aq.)-   B Ammonia/iPrOH, e.g. 50° C. for 5 hours, then ambient temperature    for 12-18 hours, then 50° C. for 9 hours.-   C For X═NH, R^(A)═C₁₋₆alkyl: R^(A)NH₂/ethylene glycol e.g. 120° C.    for 12-18 hours. For Z═O, R^(A)═C₁₋₆alkyl:    R^(A)ONa/BuOH/dimethoxyethane e.g. 93-110° C. for 12-18 hours.-   C1 NBS in CHCl₃ e.g. 0-5° C. for 30 minutes then ambient temperature    for 0.5-1 hour, then e.g. NaOMe/methanol under N₂/60-70° C./12-18    hours, then TFA/MeOH e.g. ambient temperature for 18-65 hours.-   D NBS in CHCl₃ e.g. 0-5° C. for 30 minutes then ambient temperature    for 36-48 hours.-   E NaOMe/MeOH e.g. reflux 4-6 hours.-   F TFA/MeOH e.g. ambient temperature for 18-65 hours.-   G K₂CO₃/DMF then R²Br e.g. 60° C. for 1-1.5 hours, then 50° C. for    3-6 hours, then ambient temperature for 12-72 hours then 50° C. for    3-6 hours.-   G1 K₂CO₃/DMF, then BOC-R²—Br/DMF, then 50° C. for 3 hours, then    ambient temperature for 16 hours, then 50° C. for 5 hours.-   G2 Solution in MeOH/DCM eluted through aminopropyl SPE cartridge    with MeOH/DCM.-   G3 THF/1,1′-(azodicarbonyl)dipiperidine/tributylphosphine. Stir    ambient temp. 12-18 hours.-   G4 R²P—Br, K₂CO₃/DMF, then H₂, Pd/C at ambient temp. for 18 hours,    then R²—Br, DIPEA/DMF at 50° C. for 15-24 hours.-   H HCl/methanol, then ambient temperature for 5 hours.-   H1 HCl/dioxane, then ambient temperature for 4.5 hours.

Compounds of formulae (IX), (IXA), (X), (XI), (XII), (XIII), (IXA),(XIV), (XV), (XVI), (XVII), (XVIII), and (XIX) are commerciallyavailable, for example from Sigma-Aldrich, UK, or may be prepared byanalogy with known procedures, for example those disclosed in standardreference texts of synthetic methodology such as J. March, AdvancedOrganic Chemistry, 6th Edition (2007), WileyBlackwell, or ComprehensiveOrganic Synthesis (Trost B. M. and Fleming I., (Eds.), Pergamon Press,1991), each incorporated herein by reference as it relates to suchprocedures.

Examples of other protecting groups that may be employed in thesynthetic routes described herein and the means for their removal can befound in T. W. Greene ‘Protective Groups in Organic Synthesis’, 4thEdition, J. Wiley and Sons, 2006, incorporated herein by reference as itrelates to such procedures.

For any of the hereinbefore described reactions or processes,conventional methods of heating and cooling may be employed, for exampletemperature-regulated oil-baths or temperature-regulated hot-blocks, andice/salt baths or dry ice/acetone baths respectively. Conventionalmethods of isolation, for example extraction from or into aqueous ornon-aqueous solvents may be used. Conventional methods of drying organicsolvents, solutions, or extracts, such as shaking with anhydrousmagnesium sulphate, or anhydrous sodium sulphate, or passing through ahydrophobic frit, may be employed. Conventional methods of purification,for example crystallisation and chromatography, for example silicachromatography or reverse-phase chromatography, may be used as required.Crystallisation may be performed using conventional solvents such asethyl acetate, methanol, ethanol, or butanol, or aqueous mixturesthereof. It will be appreciated that specific reaction timestemperatures may typically be determined by reaction-monitoringtechniques, for example thin-layer chromatography and LC-MS.

Where appropriate individual isomeric forms of the compounds of theinvention may be prepared as individual isomers using conventionalprocedures such as the fractional crystallisation of diastereoisomericderivatives or chiral high performance liquid chromatography (chiralHPLC).

The absolute stereochemistry of compounds may be determined usingconventional methods, such as X-ray crystallography.

Aspects of the invention are illustrated by reference to, but are in noway limited by, the following Examples.

General Experimental Details

Compounds were named using ACD/Name PRO 6.02 chemical naming softwarefrom Advanced Chemistry Developments Inc., Toronto, Ontario, M5H2L3,Canada.

Experimental details of LCMS systems A-D as referred to herein are asfollows:

System A

Column: 50 mm×2.1 mm ID, 1.7 μm Acquity HPLC BEH C₁₈

Flow Rate: 1 mL/min.

Temp: 40° C.

UV detection range: 210 to 350 nm

Mass spectrum: Recorded on a mass spectrometer using alternative-scanpositive and negative mode electrospray ionisation

Solvents: A: 0.1% v/v formic acid in water

-   -   B: 0.1% v/v formic acid acetonitrile

Gradient:

Time (min.) A % B % 0 97 3 1.5 0 100 1.9 0 100 2.0 97 3

System B

Column: 30 mm×4.6 mm ID, 3.5 μm Sunfire C₁₈ column

Flow Rate: 3 mL/min.

Temp: 30° C.

UV detection range: 210 to 350 nm

Mass spectrum: Recorded on a mass spectrometer using alternative-scanpositive and negative mode electrospray ionisation

Solvents: A: 0.1% v/v solution of formic acid in water

-   -   B: 0.1% v/v solution of formic acid in acetonitrile

Gradient:

Time (min.) A % B % 0 97 3 0.1 97 3 4.2 0 100 4.8 0 100 4.9 97 3 5.0 973

System C

Column: 50 mm×2.1 mm ID, 1.7 μm Acquity UPLC BEH C₁₈

Flow Rate: 1 mL/min.

Temp: 40° C.

UV detection range: 210 to 350 nm

Mass spectrum: Recorded on a mass spectrometer using alternative-scanpositive and negative mode electrospray ionisation

Solvents: A: 10 mM ammonium bicarbonate in water adjusted to pH10 withammonia solution

-   -   B: acetonitrile

Gradient:

Time (min.) A % B % 0 99 1 1.5 3 97 1.9 3 97 2.0 0 100

System D

Column: 50 mm×4.6 mm ID, 3.5 μm XBridge C₁₈ column

Flow Rate: 3 mL/min.

Temp: 30° C.

UV detection range: 210 to 350 nm

Mass spectrum: Recorded on a mass spectrometer using alternative-scanpositive and negative mode electrospray ionisation

Solvents: A: 10 mM ammonium bicarbonate in water adjusted to pH10 withammonia solution

-   -   B: acetonitrile

Gradient:

Time (min.) A % B % 0 99 1 0.1 99 1 4.0 3 97 5.0 3 97

Mass spectra obtained using a Floinject analysis and were obtained usingthe following conditions:

The Floinject analysis was conducted by direct injection to the massspectrometer. Solvents at 30 degrees centigrade.

The solvents employed were:

-   A=0.1% v/v solution of formic acid in water.-   B=0.1% v/v solution of formic acid in acetonitrile.

The isocratic gradient employed was:

Time (min) Flow Rate (ml/min) % A % B 0 1.5 30 70 1.5 1.5 30 70

Mass spectra were recorded at 0.3 minute on a mass spectrometer usingalternate-scan positive and negative mode electrospray ionization.

Chromatographic purification was typically performed using pre-packedsilica gel cartridges. The Flashmaster II is an automated multi-userflash chromatography system, available from Argonaut Technologies Ltd,which utilises disposable, normal phase, Solid Phase Extraction (SPE)cartridges (2 g to 100 g). It provides quaternary on-line solvent mixingto enable gradient methods to be run. Samples are queued using themulti-functional open access software, which manages solvents,flow-rates, gradient profile and collection conditions. The system isequipped with a Knauer variable wavelength UV-detector and two GilsonFC204 fraction-collectors enabling automated peak-cutting, collectionand tracking.

Solvent removal using a stream of nitrogen was performed at 30-40° C. ona GreenHouse Blowdown system available from Radleys DiscoveryTechnologies Saffron Walden, Essex, CB11 3AZ. UK

¹H NMR spectra were recorded in either CDCl₃ or DMSO-d₆ on either aBruker DPX 400 or Bruker Avance DRX or Varian Unity 400 spectrometer allworking at 400 MHz. The internal standard used was eithertetramethylsilane or the residual protonated solvent at 7.25 ppm forCDCl₃ or 2.50 ppm for DMSO-d₆.

High resolution Mass spectra were recorded on Waters Micromass(subcompany) Q-T of (Quadrupole Time of Flight) Ultima API instrument.

Mass directed autopreparative HPLC was undertaken under the conditionsgiven below. The UV detection was an averaged signal from wavelength of210 nm to 350 nm and mass spectra were recorded on a mass spectrometerusing alternate-scan positive and negative mode electrospray ionization.

Method A:

Method A was conducted on an XBridge C₁₈ column (typically 150 mm×19 mmi.d. 5 μm packing diameter) at ambient temperature. The solventsemployed were:

-   A=10 mM aqueous ammonium bicarbonate adjusted to pH 10 with ammonia    solution.-   B=acetonitrile.

Method B:

Method B was conducted on a Sunfire C₁₈ column (typically 150 mm×30 mmi.d. 5 μm packing diameter) at ambient temperature. The solventsemployed were:

-   A=0.1% v/v solution of formic acid in water.-   B=0.1% v/v solution of formic acid in acetonitrile.

Method C:

Method C was conducted on a Sunfire C₁₈ column (typically 150 mm×30 mmi.d. 5 μm packing diameter) at ambient temperature. The solventsemployed were:

-   A=0.1% v/v solution of trifluoroacetic acid in water.-   B=0.1% v/v solution of trifluoroacetic acid in acetonitrile.

Method D:

Method B was conducted on an Atlantis C₁₈ column (typically 100 mm×30 mmi.d. 5 μm packing diameter) at ambient temperature. The solventsemployed were:

-   A=0.1% v/v solution of formic acid in water.-   B=0.1% v/v solution of formic acid in acetonitrile.

EXAMPLES Intermediate 1:2,6-Dichloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purine

To 2,6-dichloropurine (25.0 g) (available from, for example, Aldrich,UK) was added ethyl acetate (260 mL), followed by p-toluenesulfonic acid(0.253 g). The mixture was heated to 50° C. and then3,4-dihydro-2H-pyran (16.8 g) was added. The reaction mixture was thenheated at 50° C. for 4 hours. The reaction mixture was evaporated invacuo to give the title compound as a yellow solid (36.9 g).

1H NMR (CDCl₃): 8.35 (1H, s), 5.77 (1H, dd), 4.20 (1H, m), 3.79 (1H, m),2.20-1.65 (6H, m).

Intermediate 2: 2-Chloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

2,6-Dichloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purine (36.9 g) was heatedwith 2M ammonia in isopropanol (250 mL) at 50° C. for 5 hours. Afterstanding at ambient temperature overnight, a further quantity of 2Mammonia in isopropanol (100 mL) was added to break up the resultant cakeand the reaction mixture was heated for a further 9 hours until thereaction was complete. To the reaction mixture was added water (70 mL)and the yellow solid filtered off. The solid was washed with isopropylalcohol:water (5:1 (v/v), 60 mL) and then air-dried under suction togive a first crop. The filtrate was re-filtered after standing overnightto isolate precipitate and both solids were dried in vacuo. The firstcrop was pure with the second crop material showing a very minorimpurity (isolated broad signal 3.5 ppm not seen in first crop) but wasotherwise identical. Solid first crop (28.4 g), solid second crop (3.42g).

1H NMR (CDCl₃): 8.01 (1H, s), 5.98 (2H, broad s), 5.70 (1H, dd), 4.16(1H, m), 3.78 (1H, m), 2.15-1.60 (6H, overlapping m).

Intermediate 2 (alternative method):2-Chloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

To a solution of 2,6-dichloropurine (25 g) (available from, for example,Aldrich, UK) in dry ethyl acetate (200 ml) was added p-toluenesulfonicacid monohydrate (235 mg). The reaction was heated to 50° C. and3,4-dihydro-2H-pyran (18.1 ml) was added in one go. The reaction wasallowed to stir at 50° C. for 1 hour and the solvent was removed underreduced pressure. This afforded a yellow solid. A suspension of thissolid (˜36 g) in 2.0M ammonia in isopropanol (460 ml) was heated undernitrogen at 60° C. for 4 hours with an attached condenser. The reactionwas poured into water (50 ml) and left to cool overnight. Theprecipitate was filtered and dried on a rotary evaporator (60° C.) for30 minutes to afford the title compound as an off-white solid, 31 g(93%, 2 steps).

MS calcd for (C₁₀H₁₂ClN₅O)⁺=254, 256

MS found (electrospray): (M)⁺=254, 256 (3:1)

¹H NMR ((CD₃)₂SO): δ 8.43 (1H, s), 7.82 (2H, s), 5.55 (1H, dd), 4.00(1H, m), 3.69 (1H, m), 2.21 (1H, m), 1.95 (2H, m), 1.74 (1H, m), 1.56(2H, m).

Intermediate 3: 2-Butoxy-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

To butan-1-ol (76 mL) was added portion wise sodium tert-butoxide (15.2g) (Note: reaction mixture gets warm). The above was stirred untilhomogeneous (˜15 min) before2-chloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (10.0 g) was thenadded to the resultant pale yellow solution. The reaction mixture wasthen heated to 100° C., overnight. The reaction mixture was stripped toremove as much butan-1-ol as possible before being partitioned betweendiethyl ether and water. The diethyl ether phase was separated and theaqueous re-extracted further with diethyl ether. Combined organic layersdried over magnesium sulphate (anhydrous). Magnesium sulphate wasfiltered off and filtrate stripped to give brown viscous oil which wasazeotroped with toluene (3 times) and placed under high vacuumovernight, transferred to new flask with dichloromethane and stripped,placed under high vacuum to give the title compound as a brown glass(9.45 g).

1H NMR (CDCl₃): 7.85 (1H, s), 5.92 (2H, broad s), 5.64 (1H, d), 4.32(2H, t), 4.14 (1H, m), 3.75 (1H, m), 2.10-1.95 (3H, overlapping m),1.81-1.58 (5H, overlapping m), 1.50 (2H, m), 0.97 (3H, t).

Intermediate 4:8-Bromo-2-butoxy-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

2-(Butoxy)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (9.45 g) wasdissolved in chloroform (50 mL) and cooled to 0° C. (ice-bath). To thissolution was added portion wise N-bromosuccinimide (6.07 g) keeping thetemperature below 3° C. This gave a dark green solution, stirred at 2.5°C. for 30 minutes before allowing to warm to room temperature and thenstirring for 6 hours. The reaction mixture was then washed with water(100 mL, twice). Organic phase was dried/separated using a hydrophobicfrit and evaporated to give a dark brown gum which was purified bysilica chromatography (120 g) (ISCO) using a gradient elution of 0-50%ethyl acetate:cyclohexane to afford the title compound as a pale yellowsolid (8.37 g).

1H NMR (CDCl₃): 5.61 (1H, dd), 5.49 (2H, broad s), 4.32 (2H, m), 4.17(1H, m), 3.71 (1H, m), 3.04 (1H, m), 2.11 (1H, broad d), 1.89-1.45 (6H,overlapping m), 1.50 (2H, m), 0.97 (3H, t).

Intermediate 5:2-Butoxy-8-methoxy-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

8-Bromo-2-(butoxy)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (8.37g) was heated to reflux with 25% sodium methoxide in methanol (14.4 mL)and methanol (65 mL) for 4.5 hours. The reaction mixture wasconcentrated under reduced pressure and partitioned between ethylacetate and saturated ammonium chloride solution. Separated organicphase and repeated extraction into ethyl acetate. Combined organicphases and washed with brine (twice). The organic phase was passedthrough a hydrophobic frit after separating aqueous and was evaporatedto give a light brown gum which was placed under high vacuum to give afoam (7.52 g) which collapsed to a gum (7.34 g) at ambient pressure andsolidified overnight to give the title compound as a yellow amorphoussolid.

MS calcd for (C₁₅H₂₃N₅O₃)⁺=321

MS found (electrospray): (M+H)⁺=322

1H NMR (CDCl₃): 5.50 (1H, dd), 5.17 (2H, broad s), 4.29 (2H, t), 4.12(3H, s and 1H, m), 3.70 (1H, m), 2.77 (1H, m), 2.05 (1H, m), 1.82-1.63(6H, overlapping m), 1.50 (2H, m), 0.97 (3H, t).

Intermediate 6: 2-Butoxy-8-methoxy-9H-purin-6-amine trifluoroacetatesalt

To a solution of2-(butoxy)-8-(methoxy)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine(7.34 g) in methanol (100 mL) was added trifluoroacetic acid (10 mL).The mixture was stirred at ambient temperature over the weekend to givea suspension. The reaction mixture was concentrated to a small volume(thick slurry) before being diluted with ethyl acetate (50 mL). Theresultant slurry was filtered and washed with a small volume of ethylacetate until the filtrate was colourless. The solid remaining was driedby air and then in vacuo to give the title compound as a white solid(6.20 g). The filtrate obtained previously was concentrated to give aslurry which was diluted with a small volume of ethyl acetate (10 mL)and then filtered and dried as above. This second crop was isolated as awhite solid (0.276 g). Both crops were identical by NMR.

MS calcd for (C₁₀H₁₅N₅O₂)⁺=237

MS found (electrospray): (M+H)⁺=238

1H NMR (CD₃OD): 4.47 (2H, t), 4.15 (3H, s), 1.80 (2H, m), 1.50 (2H, m),0.99 (3H, t) (exchangeable NH₂, NH and COOH protons not observed).

Intermediate 7:N²-Butyl-9-(tetrahydro-2H-pyran-2-yl)-9H-purine-2,6-diamine

To a solution of 2-chloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine(10 g) in dry ethylene glycol (50 ml) at room temperature and undernitrogen was added n-butylamine (16 ml) in one go. The reaction washeated at 120° C. overnight. The reaction was cooled to roomtemperature, diluted with ethyl acetate (150 ml) and washed with water(2×50 ml). The organic layer was dried over MgSO₄, filtered andconcentrated in vacuo. This afforded the title compound as a viscousgreen oil (10.2 g) that was used in the next step without furtherpurification.

MS calcd for (C₁₄H₂₂N₆O)⁺=290

MS found (electrospray): (M+H)⁺=291

¹H NMR ((CD₃)₂SO): δ 7.8 (1H, s), 6.6 (2H, s), 6.2 (1H, t), 5.4 (1H,dd), 4.0 (1H, m), 3.6 (1H, m), 3.2 (2H, m), 2.2 (1H, m), 1.9 (1H, m),1.8 (1H, m), 1.7 (1H, m), 1.5 (2H, m), 1.4 (2H, m), 1.3 (2H, m), 0.9(3H, t).

Intermediate 8: N²-Butyl-8-methoxy-9H-purine-2,6-diamine trifluoroaceticacid salt

To a solution of crudeN²-butyl-9-(tetrahydro-2H-pyran-2-yl)-9H-purine-2,6-diamine (˜10.2 g) indry chloroform (100 ml) at room temperature was added N-bromosuccinimide(6.3 g) in portions over 5 minutes. The dark solution was allowed tostir at room temperature for 30 minutes. The reaction mixture was washedwith water (20 ml). The organic phase was passed through a hydrophobicfrit and concentrated in vacuo. This afforded a beige solid which wasdissolved in dry methanol (100 ml) and at room temperature undernitrogen was added sodium methoxide solution (25 wt. % in methanol, 24ml) in one go. The reaction was heated at 65° C., with a condenserattached, overnight. The reaction was cooled and concentrated in vacuo.The resultant orange residue was taken up in ethyl acetate (150 ml) andpoured into saturated aqueous ammonium chloride (50 ml). The organiclayer was separated and washed further with water (50 ml). The organiclayer was dried over MgSO₄, filtered and concentrated in vacuo. To thismaterial in dry methanol (70 ml) at room temperature was addedtrifluoroacetic acid (7 ml) in one go. The reaction was stirred for 30hours and concentrated in vacuo to yield a dark brown solid. This wastaken up in diethyl ether (20 ml) and triturated. The solid was filteredto afford the title compound as a beige solid (3.3 g, 35%, 4 steps).

MS calcd for (C₁₀H₁₆N₆O)⁺=236

MS found (electrospray): (M+H)⁺=237

¹H NMR ((CD₃)₂SO): δ 13.3-12.3 (1H, br.m), 8.6-7.3 (2H, m), 4.05 (3H,s), 3.28 (2H, m), 1.52 (2H, m), 1.33 (2H, m), 0.89 (3H, t) (remainingexchangeable protons not clear).

Intermediate 9: N-Ethyl-3-piperidinemethanol

To a stirring mixture of 3-piperidinemethanol (2 g) and potassiumcarbonate (6 g) in dry N,N-dimethylformamide (15 ml) was addediodoethane (1.53 ml). The reaction became warm and was cooled back toambient temperature using a cold water bath. After 2 hours, the solventwas stripped, the residue treated with water and extracted three timeswith ethyl acetate. The combined extracts were washed with water thenbrine, dried by passing through a phase separation cartridge andevaporated to give the title compound as a clear oil, yield 1.53 g, 61%.

MS calcd for (C₈H₁₇NO)⁺=143

MS found (electrospray): (M+H)⁺=144

¹H NMR (CDCl₃): δ 3.66 (1H, m), 3.54 (1H, m), 2.85 (1H, m), 2.67 (1H,m), 2.39 (2H, q), 2.15-2.05 (1H, m), 2.05-1.92 (1H, m), 1.8 (2H, m),1.75-1.66 (1H, m), 1.66-1.55 (1H, m), 1.15 (1H, m), 1.08 (3H, t) (OH notclear).

Intermediate 10: 3-(Bromomethyl)-1-ethylpiperidine

48% Aqueous hydrogen bromide (16 ml) was added toN-ethyl-3-piperidinemethanol (1.53 g) and the stirring mixture refluxedfor 6 hours. After cooling, the solvent was stripped, the residuetreated with water and made basic by addition of 1M aq. potassiumcarbonate. The mixture was shaken with dichloromethane, filtered toremove unwanted solid, and the filtrate separated. The aqueous layer wasfurther extracted with dichloromethane and the combined extracts washedwith dilute brine, dried by passing through a phase separation cartridgeand stripped to give the title compound as a pale oil (1.4 g).

¹H NMR (CDCl₃): δ 3.32 (2H, m), 3.0 (1H, m), 2.81 (1H, m), 2.41 (2H, m),2.02-1.53 (6H, m), 1.12-1.0 (4H, m).

Intermediate 11:2-Butoxy-9-[(1-ethyl-3-piperidinyl)methyl]-8-methoxy-9H-purin-6-amine

A stirring mixture of 2-butoxy-8-methoxy-9H-purin-6-aminetrifluoroacetate salt (200 mg) and potassium carbonate (236 mg) in dryN,N-dimethylformamide (2 ml) was heated with stirring at 60° C. for 1hour. 3-(Bromomethyl)-1-ethylpiperidine (141 mg) was added and thestirring mixture heated at 50° C. for 3 hours. After 16 hours at ambienttemperature, heating at 50° C. was continued for a further 3 hours tocomplete the reaction. Water was added and the mixture extracted threetimes with ethyl acetate. The combined extracts were washed with waterthen brine, dried by passing through a phase separation cartridge andstripped to give a brown oil. This was purified by C₁₈ reverse phasechromatography using water (containing 0.1% formic acid)-acetonitrile(containing 0.05% formic acid) as eluent (10-45%) and the appropriatefractions combined and evaporated to remove acetonitrile. The remainingaqueous mixture was made basic with saturated sodium hydrogen carbonate,extracted three times with dichloromethane and the combined extractsdried by passing through a phase separation cartridge then evaporated toafford the title compound as a white solid (99 mg).

MS calcd for (C₁₈H₃₀N₆O₂)⁺=362

MS found (electrospray): (M+H)⁺=363

¹H NMR (CDCl₃): δ 5.09 (2H, s), 4.27 (2H, t), 4.09 (3H, s), 3.81 (2H,m), 2.82 (1H, m), 2.73 (1H, m), 2.36 (2H, m), 2.18 (1H, m), 1.87 (1H,m), 1.82-1.59 (5H, m), 1.50 (3H, m), 1.02 (4H, m), 0.96 (3H, t).

Intermediate 12:N²-Butyl-9-[(1-ethyl-3-piperidinyl)methyl]-8-methoxy-9H-purine-2,6-diamine

A stirring mixture of N²-butyl-8-methoxy-9H-purine-2,6-diaminetrifluoroacetic acid salt (200 mg) and potassium carbonate (236 mg) indry N,N-dimethylformamide (2 ml) was heated with stirring at 60° C. for1 hour. 3-(Bromomethyl)-1-ethylpiperidine (141 mg) was added and thestirring mixture heated at 50° C. for 6 hours. After 72 hours at ambienttemperature heating at 50° C. was continued for a further 6 hours tocomplete the reaction. Water was added and the mixture extracted threetimes with ethyl acetate. The combined extracts were washed with waterthen brine, dried by passing through a phase separation cartridge andstripped to give a brown oil. This was purified by C₁₈ reverse phasechromatography using water (containing 0.1% formic acid)-acetonitrile(containing 0.05% formic acid) as eluent (5-35%) and the appropriatefractions combined and evaporated to remove acetonitrile. The remainingaqueous mixture was made basic with saturated sodium hydrogen carbonate,extracted three times with dichloromethane and the combined extractsdried by passing through a phase separation cartridge then evaporated toafford the title compound as a clear oil (120 mg).

MS calcd for (C₁₈H₃₁N₇O)⁺=361

MS found (electrospray): (M+H)⁺=362

¹H NMR (CDCl₃): δ 4.89 (2H, s), 4.56 (1H, m), 4.07 (3H, s), 3.75 (2H,d), 3.36 (2H, m), 2.83 (1H, m), 2.75 (1H, m), 2.36 (2H, m), 2.17 (1H,m), 1.87 (1H, m), 1.81-1.50 (6H, m), 1.40 (2H, m), 1.03 (4H, m), 0.94(3H, t).

Intermediate 13: 1,1-Dimethylethyl4-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-Purin-9-yl]methyl}-1-piperidinecarboxylate

Potassium carbonate (650 mg) was added to a solution of2-butoxy-8-methoxy-9H-purin-6-amine trifluoroacetate salt (550 mg) indry N,N-dimethylformamide (5.5 ml) and the reaction mixture heated at60° C. for 1 hour. 1,1-Dimethylethyl4-(bromomethyl)-1-piperidinecarboxylate (500 mg) was added usingadditional DMF (1.5 ml) to transfer the residual bromide and thereaction mixture stirred at 50° C. for 3 hours. After 16 hours at roomtemperature, heating at 50° C. was continued for another 5 hours tocomplete the reaction. Water was added and the reaction mixtureextracted three times with ethyl acetate. The combined organic extractswere washed with water, dried over anhydrous sodium sulfate, filtered,concentrated and dried under high vacuum. Purification by chromatographyon silica gel eluting with a gradient of 1-2.5% methanol in chloroformafforded the title compound as yellow solid (640 mg).

¹H NMR (CDCl₃): δ 5.14 (2H, s), 4.27 (2H, t), 4.11 (3H, s) 3.81 (2H, d),2.65 (2H, m), 2.03 (1H, m), 1.77 (3H, p), 1.57-1.45 (14H, m), 1.26-1.17(2H, m), 0.97 (3H, t).

Intermediate 14: 1,1-Dimethylethyl(3R)-3-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 13 from2-butoxy-8-methoxy-9H-purin-6-amine trifluoroacetate salt and1,1-dimethylethyl (3S)-3-(bromomethyl)-1-piperidinecarboxylate.

¹H NMR (CDCl₃): δ 5.13 (2H, s), 4.26 (2H, t), 4.11 (3H, s), 3.80-3.88(4H, m), 2.82 (1H, t), 2.68 (1H, m), 2.08 (1H, m), 1.78 (2H, m), 1.68(2H, m), 1.41-1.54 (13H, m), 0.96 (3H, t).

Intermediate 15: 1,1-Dimethylethyl(3R)-3-(bromomethyl)-1-piperidinecarboxylate

Tetrabromomethane (1.23 g) was added to a solution of 1,1-dimethylethyl(3R)-3-(hydroxymethyl)-1-piperidinecarboxylate (500 mg) in methylenechloride (2.7 mL). The reaction mixture was cooled to 0° C. and asolution of triphenylphosphine (731 mg) in methylene chloride (2.7 mL)was slowly added. After 1 hour at 0° C., the reaction mixture wasconcentrated and directly purified by chromatography on silica geleluting with heptane/ethyl acetate 1:15 followed 1:10 to yield the titlecompound as a slightly yellow oil (627 mg).

TLC ethyl acetate/heptane 1:2:Rf 0.55

Intermediate 16: 1,1-Dimethylethyl(3S)-3-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 13 from2-butoxy-8-methoxy-9H-purin-6-amine trifluoroacetate salt and1,1-dimethylethyl (3R)-3-(bromomethyl)-1-piperidinecarboxylate.

¹H NMR (CDCl₃): δ 5.46 (2H, s), 4.27 (2H, t), 4.11 (3H, s), 3.79-3.88(4H, m), 2.82 (1H, m), 2.68 (1H, m), 2.08 (1H, m), 1.76 (2H, m), 1.70(2H, m), 1.41-1.52 (13H, m), 0.96 (3H, t).

Intermediate 17: 1,1-Dimethylethyl4-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 13 from2-butoxy-8-methoxy-9H-purin-6-amine trifluoroacetate salt and1,1-dimethylethyl 4-(2-bromoethyl)-1-piperidinecarboxylate. TLCchloroform/methanol 9:1:Rf 0.81

Intermediate 18: 2-(Butyloxy)-8-(methyloxy)-9H-purin-6-amine

2-(Butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate (2.4 g,6.83 mmol) was dissolved in methanol/dichloromethane (1:1, 20 ml) andloaded onto a preconditioned aminopropyl SPE (50 g). The cartridge waseluted with methanol/dichloromethane (1:1, 200 ml) and the solventconcentrated in vacuo to give the title compound as a white solid (1.38g).

LCMS (System A): t_(RET)=0.65 min; MH⁺ 238

Intermediate 19:2-(Butyloxy)-9-[(1-ethyl-4-piperidinyl)methyl]-8-(methyloxy)-9H-purin-6-amine

2-(Butyloxy)-8-(methyloxy)-1H-purin-6-amine (300 mg, 1.264 mmol),(1-ethyl-4-piperidinyl)methanol (362 mg, 2.53 mmol) andtributylphosphine (0.624 ml, 2.53 mmol) were dissolved in THF (12 ml).1,1′-(Azodicarbonyl)dipiperidine (638 mg, 2.53 mmol) was added and thereaction mixture stirred at rt overnight. The solvent was removed invacuo and the residue purified by column chromatography, loading indichloromethane and purified on Flashmaster II silica (Si) 20 g using a0-100% ethyl acetate in cyclohexane+0-20% methanol (+1% Et₃N) gradientover 30 mins. The appropriate fractions were combined and evaporated invacuo. The material (300 mg) was dissolved in 1:1 MeOH:DMSO 3 ml andre-purified by Mass Directed AutoPrep (Method A). The solvent was driedunder a stream of nitrogen in the Radleys blowdown apparatus to give thetitle compound as a clear gum (60 mg). LCMS (System A): t_(RET)=0.57min; MH⁺ 363

Intermediate 20: 2-(1-Ethyl-4-piperidinyl)ethanol

To a stirring solution of 2-(4-piperidinyl)ethanol (1 g, 7.74 mmol) andpotassium carbonate (2.67 g, 19.35 mmol) in dry DMF (10 ml) was addediodoethane (0.687 ml, 8.51 mmol). The reaction mixture was allowed tostir at room temperature for 18 hours. The solvent was partially removedin vacuo and the residue partitioned between water (20 ml) and ethylacetate (20 ml). The aqueous was washed with further ethyl acetate andthe combined organics dried (hydrophobic frit) and concentrated in vacuoto give the title compound as a mixture with residual DMF as a clearoil, 1.55 g

1H NMR (400 MHz, DMSO-d₆) δ ppm 0.96 (t, J=7.2 Hz, 3H) 1.03-1.15 (m, 2H)1.29-1.37 (m, 3H) 1.55-1.63 (m, 2H) 1.72-1.81 (m, 2H) 2.25 (q, J=7.3 Hz,2H) 2.73 (s, 6H residual DMF) 2.77-2.84 (m, 2H) 2.89 (s, 6H residualDMF) 3.31 (s, 1 H) 3.38-3.45 (m, 2H) 4.27-4.32 (m, 1H) 7.95 (s, 2Hresidual DMF).

Intermediate 21:2-(Butyloxy)-9-[2-(1-ethyl-4-piperidinyl)ethyl]-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 19 from2-(butyloxy)-8-(methyloxy)-1H-purin-6-amine and2-(1-ethyl-4-piperidinyl)ethanol.

LCMS (System A): t_(RET)=0.61 min; MH⁺ 377

Intermediate 22: 3-(1-Ethyl-4-piperidinyl)-1-propanol

Prepared similarly to Intermediate 20 from 3-(4-piperidinyl)-1-propanolhydrochloride. 1H NMR (400 MHz, DMSO-d₆) δ ppm 0.96 (t, J=7.2 Hz, 3H)1.01-1.23 (m, 5H) 1.36-1.45 (m, 2H) 1.56-1.63 (m, 2H) 1.72-1.81 (m, 2H)2.22-2.29 (m, 2H) 2.73 (s, 17H residual DMF) 2.81 (d, J=11.54 Hz, 2H)2.86-2.92 (m, 18H residual DMF) 3.30-3.39 (m, 3H) 4.30-4.36 (m, 1H) 7.95(s, 8H residual DMF)

Intermediate 23:2-(Butyloxy)-9-[3-(1-ethyl-4-piperidinyl)propyl]-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 19 from2-(butyloxy)-8-(methyloxy)-1H-purin-6-amine and2-(1-ethyl-4-piperidinyl)-1-propanol.

LCMS (System B): t_(RET)=1.31 min; MH⁺ 391

Intermediate 24: 4-(1-Ethyl-4-piperidinyl)-1-butanol

To stirring solution of 4-(4-piperidinyl)-1-butanol hydrochloride (4.51g, 23.28 mmol) and potassium carbonate (8.04 g, 58.2 mmol) in dryacetonitrile (60 ml) was added iodoethane (2.070 ml, 25.6 mmol). Thereaction mixture was allowed to stir at room temperature for 4 hours.The reaction mixture was concentrated in vacuo and the residuepartitioned between water (20 ml) and ethyl acetate (30 ml). The aqueouswas re-extracted with ethyl acetate (1×30 ml) then dichloromethane (1×30ml), the organic layers dried by passage through a hydrophobic frit),combined and concentrated in vacuo to give the title compound as ayellow gum (2.41 g).

MS (Floinject): MH⁺ 186

Intermediate 25:2-(Butyloxy)-9-[4-(1-ethyl-4-piperidinyl)butyl]-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 19 from2-(butyloxy)-8-(methyloxy)-1H-purin-6-amine and2-(1-ethyl-4-piperidinyl)-1-butanol.

LCMS (System B): t_(RET)=1.45 min; MH⁺ 405

Intermediate 26: Phenylmethyl 2-(2-bromoethyl)-1-piperidinecarboxylate

To a solution of phenylmethyl 2-(2-hydroxyethyl)-1-piperidinecarboxylate(1.76 g, 6.70 mmol) in anhydrous dichloromethane (29 mL) was addedcarbon tetrabromide (4.44 g, 13.39 mmol). The resulting solution wascooled in ice/water. A solution of triphenylphosphine (1.76 g, 6.70mmol) in 10 ml dry DCM was added dropwise over 30 mins. After completeaddition the reaction was allowed to warm slowly to ambient temperatureand stirring continued overnight. The reaction solution was reduced involume to <10 ml (opaque) and this was loaded onto a 100 g silicacartridge and purified by chromatography on a Flashmaster 2 using agradient of 0-25% ethyl acetate in cyclohexane over 40 minutes. Productfractions were combined and evaporated in vacuo to give the titlecompound as a colourless oil (1.62 g).

LCMS (System B): t_(RET)=3.24 min; MH⁺ 326/328

Intermediate 27: Phenylmethyl2-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate

2-(Butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate (1.346 g,3.83 mmol) was heated with anhydrous potassium carbonate (2.118 g, 15.33mmol) in dry DMF (17 ml) at 60° C. for 1 hour. Phenylmethyl2-(2-bromoethyl)-1-piperidinecarboxylate (1.500 g, 4.60 mmol) was addedand the reaction mixture heated at 50° C. overnight (20 hours). Thereaction mixture was partitioned between water (250 ml) and ethylacetate (150 ml). The aqueous was further extracted with 2×100 ml ethylacetate. The combined organic layers were washed with 100 ml brine andpassed through a hydrophobic frit to dry, then stripped to dryness(rotary evaporator). The residue was dissolved in DCM and loaded onto a70 g silica cartridge and purified by chromatography using a gradient0-100% ethyl acetate in dichloromethane+0-12% MeOH finish on aFlashmaster 2. Appropriate fractions were combined and evaporated invacuo. The material was re-purified by chromatography on silica (70 gcartridge using a gradient of 0-100% ethyl acetate in dichloromethaneover 40 mins. and subsequently a flush of 0-100% ethyl acetate inDCM+0-20% MeOH). Product fractions combined and evaporated in vacuo togive the title compound as a colourless oil (0.342 g).

LCMS (System B): t_(RET)=2.82 min; MH⁺ 483

Intermediate 28:2-(Butyloxy)-9-[2-(1-ethyl-2-piperidinyl)ethyl]-8-(methyloxy)-9H-purin-6-amine

Phenylmethyl2-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate(425 mg, 0.881 mmol) in ethanol (50 ml) was hydrogenated over palladiumon carbon (187 mg, 0.176 mmol) at ambient temperature over the weekend.The mixture was filtered through a Celite cartridge under N₂, washedwith EtOH and evaporated in vacuo. The residue was purified by MDAP(Method A) but the fractions contained two products. The fractions wereevaporated and material was dissolved in 4 ml 1:1 DMSO:MeOH.

A portion of the solution (3 ml) containing2-(butyloxy)-8-(methyloxy)-9-[2-(2-piperidinyl)ethyl]-9H-purin-6-amine(approx 140 mg, 0.402 mmol) was treated with ethyl iodide (0.032 ml,0.402 mmol) and DIPEA (0.140 ml, 0.804 mmol). The reaction was stirredat ambient temperature in a capped vial overnight. Methanol was added togive solution and this was purified by MDAP (Method A). Productfractions were evaporated under N₂ in a Radleys blow down unit. Thetitle compound was obtained as a white solid (103 mg).

LCMS (System B): t_(RET)=2.86 min; MH⁺ 377

Intermediate 29: Phenylmethyl2-(3-hydroxypropyl)-1-piperidinecarboxylate

3-(2-Piperidinyl)-1-propanol (8.69 g, 60.7 mmol) was stirred inacetonitrile (90 ml) with triethylamine (10.40 mL, 74.6 mmol) under N₂and cooled in an ice bath. Benzyl chloroformate (9.53 ml, 66.7 mmol) wasadded dropwise. After complete addition the reaction was allowed to warmto ambient temperature and stirring then continued overnight. Thesuspension was filtered and the filtrate evaporated to dryness. Theresidue was partitioned between ethyl acetate and water. The organicphase was washed with saturated brine, passed through a hydrophobic fritand evaporated to dryness. The residue was purified by chromatography onsilica (330 g silica RediSep column, loaded in DCM) using a 0-50% ethylacetate in cyclohexane gradient over 40 mins. with a 50-100% flush ofethyl acetate on an ISCO Companion. No peaks were detected (254 nm, 280nm) so the waste was evaporated in vacuo to recover the material. Thematerial was re-columned using identical conditions as before butdetecting at 220 nm and collecting all the eluent. The main product peakwas collected and evaporated in vacuo to give the title compound as ayellow oil (6.15 g). LCMS (System B): t_(RET)=2.46 min; MH⁺ 278

Intermediate 30: Phenylmethyl 2-(3-bromopropyl)-1-piperidinecarboxylate

To a solution of phenylmethyl2-(3-hydroxypropyl)-1-piperidinecarboxylate (2.14 g, 7.72 mmol) inanhydrous dichloromethane (34 ml) was added carbon tetrabromide (5.12 g,15.43 mmol)). The resulting solution was cooled in ice/water. A solutionof triphenylphosphine (4.05 g, 15.43 mmol) in 10 ml dry DCM was addeddropwise over 30 mins., producing a deep amber/brown solution. Aftercomplete addition the reaction was allowed to warm slowly to ambienttemperature and stirring continued overnight. The reaction mixture wasfiltered to remove the precipitate, washed with ether and the filtrateevaporated to approx 10 ml. This was then loaded onto a 100 g silicacartridge and purified by chromatography using a gradient of Flashmaster0-25% ethylacetate in cyclohexane over 40 mins. on a Flashmastercollecting all the eluent. The product peak was identified by TLC andthe fractions combined and evaporated in vacuo to give the titlecompound as a clear oil (2.13 g).

LCMS (System B): t_(RET)=3.44 min; MH⁺ 340/342

Intermediate 31: Phenylmethyl2-{3-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate

2-(Butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate (1.834 g,5.22 mmol) was heated at 60° C. with potassium carbonate (2.89 g, 20.88mmol) in DMF (23 ml) for 1 hour. Phenylmethyl2-(3-bromopropyl)-1-piperidinecarboxylate (2.131 g, 6.26 mmol) was addedand heating continued at 50° C. overnight (20 hours). The reactionmixture was partitioned between water (250 mL) and ethyl acetate (150mL). The aqueous was further extracted with ethyl acetate (100 ml). Thecombined organic layers were washed with brine (100 ml) and passedthrough a hydrophobic frit to dry, then stripped to dryness (rotaryevaporator) to give an orange liquid. The material was loaded onto 2×70g aminopropyl cartridge and eluted on the Flashmaster system in gradientof 0-100% ethylacetate in cyclohexane over 40 mins. Appropriate productfractions were combined and evaporated in vacuo to give the titlecompound as a clear oil (1.16 g).

LCMS (System B): t_(RET)=2.92 min; MH⁺ 497

Intermediate 32:2-(Butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amine

Phenylmethyl2-{3-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate(1.16 g, 2.336 mmol) in ethanol (130 ml) was hydrogenated over 10%palladium on carbon (0.497 g, 0.467 mmol) at ambient temperatureovernight. The mixture was filtered through a Celite cartridge under N₂,washed with EtOH and evaporated in vacuo to give the title compound as acream solid (0.66 g). LCMS (System B): t_(RET)=1.29 min; MH⁺ 363

Intermediate 33: Phenylmethyl3-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate

To a solution of 2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine.trifluoroacetate salt (2.56 g, 7.29 mmol) in DMF (60 ml) was addedpotassium carbonate (4.03 g, 29.1 mmol) and the mixture was left to stirat 60° C. for one hour under an atmosphere of nitrogen. Reaction wasthen cooled to room temperature and to this was added phenylmethyl3-(bromomethyl)-1-piperidinecarboxylate (2.275 g, 7.29 mmol). Thereaction was bought back up to 50° C. and left to stir overnight. Thereaction mixture was diluted with water (˜40 ml) and partitioned with asolvent mix of 1:1 ethyl acetate:DCM (40 ml). The organic layer wasseparated using hydrophobic frit and was concentrated in vacuo to givepale yellow thick oil. The crude material was dissolved in 1:1 DMSO:MeOH(5 ml) and half of this solution was initially purified on reverse-phasechromatography using a high pH system on a 330 g C₁₈ silica column. Thegradient used was the following:

-   1 CV=40% Solvent B in A-   2CV=60% Solvent B in A-   6CV=80% Solvent B in A-   1 CV=95% Solvent B in A-   0.2CV=95% Solvent B in A-   1.8CV=100% Solvent B-   Solvent A=Water with 10 mmol ammonium bicarbonate and NH₃ (pH=10)-   Solvent B=Acetonitrile with 0.1% NH₃-   (CV=Column Volume)

The fractions which were shown to contain a required isomer by LCMSanalysis were combined and concentrated in vacuo and the remaining mixedfractions were combined separately and concentrated in vacuo.

It was found that in the flask which contained the remaining half of thecrude material that needed to be purified, something had precipitated.This was filtered and washed with cold DMSO to afford a whitecrystalline material. The mixed fractions from the chromatography wererecrystallised from DMSO. Combining the material from the chromatographyand the recrystallised material gave the title compound as a white solid(1.38 g).

LCMS (System C): t_(RET)=3.13 min; MH⁺ 469

Intermediate 34:2-(Butyloxy)-8-(methyloxy)-9-(3-piperidinyl)methyl)-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl3-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate.

LCMS (System C): t_(RET)=2.25 min; MH⁺ 335

Intermediate 35:2-(Butyloxy)-9-[(1-cyclopentyl-3-piperidinyl)methyl]-8-(methyloxy)-9H-purin-6-amine

2-(Butyloxy)-8-(methyloxy)-9-(3-piperidinylmethyl)-9H-purin-6-amine(33.4 mg, 0.1 mmol) was suspended in DMF (0.4 ml) and heated brieflywith a heat gun to give a solution. To this was added iodocyclopentane(0.012 mL, 0.100 mmol) (dispensed as 112 ul of a solution of 120 uliodopentane in 1 ml DMF), and DIPEA (0.035 mL, 0.200 mmol) and a furtherDMF (88 ul) to give a total of 0.6 ml DMF. The reaction was stirred in astoppered vial at ambient temperature overnight. An extra 0.5 equivalentof iodocyclopentane was added and stirring continued for a further 24hours. A further 0.5 equivalent of iodocyclopentane was added andstirring continued over the weekend.

The reaction was repeated on the same scale using a total volume of DMF(0.5 ml) in a Radleys Greenhouse reaction station at 50° C. withstirring under N₂ for 22 hours. A further 1 equivalent iodocyclopentanewas added and heating continued over the weekend.

The reactions were combined and purified by MDAP (Method A). Appropriatefractions were combined blown down in a Radleys blown down unit under N₂to give the title compound as a colourless oil (46.5 mg).

LCMS (System B): t_(RET)=1.34 min; MH⁺ 403

Intermediate 36: Phenylmethyl 3-(2-hydroxyethyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 29 from 2-(3-piperidinyl)ethanol.

LCMS (System B): t_(RET)=2.32 min; MH⁺ 264

Intermediate 37: Phenylmethyl 3-(2-bromoethyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 26 from phenylmethyl3-(2-hydroxyethyl)-1-piperidinecarboxylate

LCMS (System D): t_(RET)=3.37 min; MH⁺ 326/328

Intermediate 38: Phenylmethyl3-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 27 from phenylmethyl3-(2-bromoethyl)-1-piperidinecarboxylate and2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate.

LCMS (System D): t_(RET)=3.38 min; MH⁺ 483

Intermediate 39:2-(Butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl3-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=2.42 min; MH⁺ 349

Intermediate 40:2-{[(1S)-1-Methylbutyl]oxy}-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

Method A

Sodium t-butoxide (48.5 g, 505 mmol) was added portionwise to(S)-2-pentanol (185 ml) (available from, for example, Julich ChiralSolutions, Germany) at room temperature stirred until homogeneous (Notereaction is exothermic).2-Chloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (32 g, 126 mmol)was added and the reaction mixture heated at 70° C. for 72 hours. Thereaction was cooled to room temperature and partitioned between ethylacetate (500 ml) and water (500 ml). The organic phase was washed withsaturated sodium chloride solution (100 ml), dried (MgSO₄), filtered andevaporated. The residue was triturated with ether and the solid materialfiltered. The precipitate was re-washed with ether and the filtratescombined and evaporated. The crude material (ca. 30 g) was dissolved inDMSO:methanol (1:1) and purified by chromatography on a reverse-phase(C₁₈) column (330 g) using a gradient of 25-65% acetonitrile (+0.1%TFA)-water (+0.1% TFA) over 8 column volumes, the fractions wereimmediately neutralised with saturated aqueous sodium carbonatesolution. Appropriate fractions were combined and partitioned betweendichloromethane and saturated aqueous sodium hydrogen carbonate. Theorganic phase was dried by passage through a hydrophobic frit, filteredand evaporated to give the title compound as a pale cream foam (14.97g).

LCMS (System B): t_(RET)=2.21 min; MH⁺ 306

Method B

Sodium t-butoxide (206 g, 2.144 mol) was added to (S)-2-pentanol (720ml, 6.58 mol) (available from, for example, Julich Chiral Solutions,Germany) in a 2 L round bottomed flask. The mixture was stirred and 50°C. until all the sodium t-butoxide had dissolved.2-Fluoro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (130 g, 548 mmol)was then added in portions over 5 minutes. After 3 hours LCMS analysisindicated complete consumption of the starting material and the mixturewas poured into ice/water (3 L) and then extracted with methyl t-butylether. This resulted in emulsion formation and the mixture was filteredthrough Celite and the organic phase was separated. The aqueous layerwas then treated with solid NaCl and then re-extracted with methylt-butyl ether. The organic extracts were combined and washed with brine,dried over magnesium sulfate, filtered and then evaporated to yield thetitle compound as a pale brown gum (158.59 g).

LCMS (System D): t_(RET)=2.65 min; MH⁺ 306

Intermediate 41:8-Bromo-2-{[(1S)-1-methylbutyl]oxy}-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

N-Bromosuccinimide (12.16 g, 68.3 mmol) was added portionwise over 5mins. to a stirred solution of2-{[(1S)-1-methylbutyl]oxy}-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine(14.9 g, 48.8 mmol) in chloroform (80 ml) at <5° C. under an atmosphereof nitrogen. The reaction mixture was stirred at <5° C. for 5 hours thenwashed with saturated sodium hydrogen carbonate solution (80 ml) thenwater (80 ml). The foam was dissolved in DCM (50 ml) and washed withwater (50 ml) then brine (50 ml). The combined aqueous phases werewashed with DCM (50 ml). The combined organic layers were dried througha hydrophobic frit, and the solvent removed in vacuo to yield the titlecompound as an orange foam (18.5 g).

LCMS (System D): t_(RET)=3.06 min; MH⁺ 384/386

Intermediate 42:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

8-Bromo-2-{[(1S)-1-methylbutyl]oxy}-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine(7.1 g, 18.48 mmol) was dissolved in anhydrous methanol (70 ml) and asolution of sodium methoxide (25%) in methanol (8 ml) was added dropwiseunder an atmosphere of nitrogen. The solution was heated to reflux at90° C. for 4 hours under an atmosphere of nitrogen. Additional sodiummethoxide in methanol (25% solution, 3 ml) was added and the reactionwas stirred at 60° C. for a further 16 hours. An additional portion ofsodium methoxide in methanol (25% solution, 5 ml) was added and thereaction was stirred at 90° C. for a further 7 hours. The solvent wasremoved on the rotary evaporator and the crude product was partitionedbetween EtOAc (75 ml) and saturated ammonium chloride solution (75 ml).The organic layer was washed with brine (75 ml). The solvent was removedon the rotary evaporator to yield the title compound as a pale orangefoam (6 g).

LCMS (System D): t_(RET)=3.08 min; MH⁺ 336

Intermediate 43:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9H-burin-6-aminetrifluoroacetate salt

2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine(6 g, 17.89 mmol) was dissolved in methanol (50 ml). Trifluoroaceticacid (20.67 ml, 268 mmol) was added dropwise, and the mixture stirred at2° C. for 72 hours under an atmosphere of nitrogen. The solvent wasremoved in vacuo, and the resulting solid was washed with ethyl acetateand filtered. The filtrate was stripped and the residue washed withethyl acetate. The combined solid residues were dried in the vacuum ovenfor 2 hours to give the title compound as an off white solid (5.3 g).

LCMS (System C): t_(RET)=0.76 min; MH⁺ 252

Intermediate 44: Phenylmethyl3-{2-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-aminetrifluoroacetate salt and phenylmethyl3-(2-bromoethyl)-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=3.47 min; MH⁺ 497

Intermediate 45:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl3-{2-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=2.58 min; MH⁺ 363

Intermediate 46:9-[2-(1-Ethyl-3-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

A solution of2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amine(45 mg, 0.124 mmol), iodoethane (0.012 ml, 0.149 mmol) and triethylamine(0.035 mL, 0.248 mmol) in DMF (3 ml) was heated at 50° C. for 18 hours.

The solvent was dried under a stream of nitrogen in the Radleys blowdownapparatus to give the crude product. The sample was redissolved in 1:1DMSO:MeOH (1 ml) and purified by Mass Directed AutoPrep (Method A). Thesolvent was evaporated from the appropriate fractions under a stream ofnitrogen to give the title compound as a colourless oil (35.4 mg).

LCMS (System D): t_(RET)=3.06 min; MH⁺ 391

Intermediate 47:2-{[(1S)-1-Methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-3-piperidinyl]ethyl}-8-(methyloxy)-9H-burin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand 2-iodopropane. LCMS (System D): t_(RET)=3.12 min; MH⁺ 405

Intermediate 48: Phenylmethyl3-(3-hydroxypropyl)-1-piperidinecarboxylate

1-({[(Phenylmethyl)oxy]carbonyl}oxy)-2,5-pyrrolidinedione (8.70 g), 34.9mmol) was added portionwise to a stirred mixture of3-(3-piperidinyl)-1-propanol (5.02 g, 35 mmol) and triethylamine (5 ml,3.63 g, 35.9 mmol) in dichloromethane (100 ml) at room temperature. Theresultant mixture was allowed to stand at room temperature for 18 hours.The reaction mixture was washed with saturated aqueous sodium hydrogencarbonate (100 ml). The organic phase was dried (MgSO₄), filtered andevaporated. The sample was purified by chromatography on silica (100 gcartridge loaded in dichloromethane) using a gradient of 0-100% ethylacetate-cyclohexane over 40 mins. The appropriate fractions werecombined and evaporated in vacuo to give the title compound as acolourless liquid (8.45 g).

LCMS (System B): t_(RET)=2.45 min; MH⁺ 278

Intermediate 49: Phenylmethyl 3-(3-bromopropyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 30 from phenylmethyl3-(3-hydroxypropyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=3.44 min; MH⁺ 340/342

Intermediate 50: Phenylmethyl3-{3-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 3-(3-bromopropyl)-1-piperidinecarboxylate. LCMS (System D):t_(RET)=3.39 min; MH⁺ 497

Intermediate 51:2-(Butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl3-{3-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=2.43 min; MH⁺ 363

Intermediate 52: Phenylmethyl3-{3-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-aminetrifluoroacetate salt and phenylmethyl3-(3-bromopropyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=2.94 min; MH⁺ 511

Intermediate 53:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl3-{3-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.36 min; MH⁺ 377

Intermediate 54:9-[3-(1-Ethyl-3-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand 2-iodoethane.

LCMS (System D): t_(RET)=3.04 min; MH⁺ 405

Intermediate 55: Phenylmethyl 3-(4-hydroxybutyl)-1-piperidinecarboxylate

To a solution of4-(1-{[(phenylmethyl)oxy]carbonyl}-3-piperidinyl)butanoic acid (5.01 g,16.41 mmol) in dry THF (40 ml) at 0° C. under nitrogen was added asolution of Borane-THF complex, (1M soln. in THF) (49.2 ml, 49.2 mmol),dropwise over 1 hour. The mixture was allowed to stir at 0° C. andgradually allowed to warm to rt over 20 hours. The mixture was cooled inan ice bath and cautiously quenched with dropwise addition of MeOH (20ml) stirred in the cold bath for 2 hours then quenched further with 10%2N HCl/MeOH (20 ml), stirred for 1 hour at rt and evaporated underreduced pressure. The residue was co-evaporated with methanol severaltimes. The sample was purified by chromatography on silica (100 g,loaded in dichloromethane/EtOAc) using a gradient of 0-100% ethylacetate in cyclohexane over 30 mins. collecting all 45 ml fractions onthe Flashmaster II. The appropriate fractions were combined andevaporated in vacuo to give the title compound as a colourless oil (4.55g).

LCMS (System B): t_(RET)=2.64 min; MH⁺ 292

Intermediate 56: Phenylmethyl 3-(4-bromobutyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 30 from phenylmethyl3-(4-hydroxybutyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=3.62 min; MH⁺ 354/356

Intermediate 57: Phenylmethyl3-{4-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 3-(4-bromobutyl)-1-piperidinecarboxylate. LCMS (System B):t_(RET)=3.08 min; MH⁺ 511

Intermediate 58:2-(Butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl3-{4-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.43 min; MH⁺ 377

Intermediate 59: Phenylmethyl3-{4-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-aminetrifluoroacetate salt and phenylmethyl3-(4-bromobutyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=3.11 min; MH⁺ 525

Intermediate 60:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.48 min; MH⁺ 391

Intermediate 61:9-[4-(1-Ethyl-3-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand 2-iodoethane.

LCMS (System D): t_(RET)=3.23 min; MH⁺ 419

Intermediate 62: 5-(3-Pyridinyl)-4-pentyn-1-ol

3-Bromopyridine (5.4 g, 34.2 mmol) was dissolved in triethylamine (10ml) and degassed under nitrogen. 4-Pentyn-1-ol (3.50 ml, 37.6 mmol) wasadded followed by bis(triphenylphosphine)palladium (II) chloride (0.245g, 0.349 mmol) and copper(I)iodide (0.136 g, 0.714 mmol) and theresulting mixture was stirred and heated under reflux for 20 mins. whena dark brown sludge was obtained. The mixture was cooled to rt andpartitioned between EtOAc (200 ml) and water (50 ml). The aqueous phasewas extracted further with EtOAc (2×100 ml); the combined organicextracts were dried (Na₂SO₄), filtered and evaporated in vacuo. Thematerial was purified by column chromatography. The sample was loaded indichloromethane and purified on silica (Si) 100 g using a gradient of0-100% ethyl acetate in cyclohexane over 60 mins on the Flashmaster II.The appropriate fractions were combined and evaporated in vacuo to givethe title compound as a yellow oil (4.99 g).

LCMS (System D): t_(RET)=2.55 min; MH⁺ 162

Intermediate 63: 5-(3-Piperidinyl)-1-pentanol acetate

A solution of 5-(3-pyridinyl)-4-pentyn-1-ol (4.99 g, 31.0 mmol) inacetic acid (150 mL) was hydrogenated over platinium (IV) oxide (1.4 g,6.16 mmol) for 18 hours. The mixture was filtered through a Celitecartridge, washed through with acetic acid and evaporated in vacuo togive a yellow oil. This was loaded in methanol and eluted on anaminopropyl (NH₂) cartridge (70 g) with methanol (400 ml). The solventwas evaporated in vacuo to give the title compound as a colourless oilwhich solidified after being under vacuum for 18 hours (7.4 g).

¹H NMR (CDCl₃): δ ppm 3.55-3.66 (m, 2H) 3.47 (s, 1H) 3.20-3.31 (m, 2H)2.59-2.71 (m, 1H) 2.28-2.39 (m, 1H) 1.96 (s, 3H) 1.67-1.92 (m, 4H)1.46-1.63 (m, 2H) 1.19-1.44 (m, 7H) 0.99-1.13 (m, 1H)

Intermediate 64: Phenylmethyl3-(5-hydroxypentyl)-1-piperidinecarboxylate

To a solution of 5-(3-piperidinyl)-1-pentanol acetate (7.37 g, 31.9mmol) in THF (50 ml) was added a solution of potassium hydroxide (5.36g, 96 mmol) in water (30 ml) and the mixture was stirred in an ice-waterbath. To this was added a solution of benzyl chloroformate (5.00 ml,35.0 mmol) in THF (25 mL) dropwise over a period of 40 mins. Afterstirring in the cold bath for 30 mins., the mixture was allowed to warmto rt and stirred for 5 hours. The organic solvent was removed byevaporation in vacuo and the aqueous phase was diluted further withwater (75 ml) and extracted with EtOAc (3×100 ml). The combined organicextracts was washed with saturated NaCl solution (100 ml), separated,dried (Na₂SO₄), filtered the solvent evaporated in vacuo and the residuewas purified by column chromatography. The sample was loaded indichloromethane and purified on silica (Si) 2×100 g cartridges using agradient of 0-100% ethyl acetate in cyclohexane over 40 mins. Theappropriate fractions were combined and evaporated in vacuo to give thetitle compound as a colourless oil (6.50 g).

LCMS (System B): t_(RET)=2.81 min; MH⁺ 306

Intermediate 65: Phenylmethyl 3-(5-bromopentyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 30 from phenylmethyl3-(5-hydroxypentyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=3.80 min; MH⁺ 368/370

Intermediate 66: Phenylmethyl3-{5-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]pentyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 3-(5-bromopentyl)-1-piperidinecarboxylate. LCMS (System B):t_(RET)=3.28 min; MH⁺ 525

Intermediate 67:2-(Butyloxy)-8-(methyloxy)-9-[5-(3-piperidinyl)pentyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl3-{5-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]pentyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.54 min; MH⁺ 391

Intermediate 68:2-(Butyloxy)-9-[5-(1-ethyl-3-piperidinyl)pentyl]-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-(butyloxy)-8-(methyloxy)-9-[5-(3-piperidinyl)pentyl]-9H-purin-6-amineand 2-iodoethane.

LCMS (System B): t_(RET)=1.56 min; MH⁺ 419

Intermediate 69:2-(Butyloxy)-9-{5-[1-(1-methylethyl)-3-piperidinyl]pentyl}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-(butyloxy)-8-(methyloxy)-9-[5-(3-piperidinyl)pentyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System B): t_(RET)=1.68 min; MH⁺ 433

Intermediate 70: Phenylmethyl4-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 4-(bromomethyl)-1-piperidinecarboxylate. LCMS (System B):t_(RET)=2.70 min; MH⁺ 469

Intermediate 71:2-(Butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.13 min; MH⁺ 335

Intermediate 72:9-[1-Ethyl-4-piperidinyl)methyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-1H-purin-6-aminetrifluoroacetate (250 mg, 0.684 mmol) was dissolved inmethanol:dichloromethane (1:1, 3 ml) and loaded onto an aminopropyl SPE(2 g) which had been pre-conditioned with methanol. The cartridge waseluted with methanol:dichloromethane (1:1) and the solvent concentratedto give as a cream solid (173 mg). The solid (173 mg, 0.684 mmol),1-ethyl-4-piperidinyl)methanol (196 mg, 1.369 mmol) andtributylphosphine (0.338 ml, 1.369 mmol) were dissolved in THF (6 ml)and stirred at rt for 30 mins. 1,1′-(Azodicarbonyl)dipiperidine (345 mg,1.369 mmol) was added and the reaction mixture stirred at rt overnight.The solvent was removed in vacuo and the residue purified by columnchromatographyon silica, loading in dichloromethane and eluting with agradient of 0-100% ethyl acetate in cyclohexane+0-20% methanol (+1%Et₃N) over 30 mins on the Flashmaster II. The appropriate fractions werecombined and evaporated in vacuo. The material was dissolved in 1:1MeOH:DMSO (2 ml) and re-purified by Mass Directed AutoPrep (Method A).The solvent was concentrated in vacuo to give the title compound as abrown gum (32 mg).

LCMS (System A): t_(RET)=0.63 min; MH⁺ 377

Intermediate 73: Phenylmethyl4-{[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-aminetrifluoroacetate salt and phenylmethyl4-(bromomethyl)-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=3.25 min; MH⁺ 483

Intermediate 74:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=2.30 min; MH⁺ 349

Intermediate 75:9-[(1-Ethyl-4-piperidinyl)methyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amineand iodoethane.

LCMS (System D): t_(RET)=2.82 min; MH⁺ 377

Intermediate 76:2-{[(1S)-1-Methylbutyl]oxy}-9-{[1-(1-methylethyl)-4-piperidinyl]methyl}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amineand 2-iodopropane.

LCMS (System D): t_(RET)=2.96 min; MH⁺ 391

Intermediate 77: Phenylmethyl4-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 4-(2-bromoethyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=2.90 min; MH⁺ 483

Intermediate 78:2-(Butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=2.23 min; MH⁺ 349

Intermediate 79:2-(Butyloxy)-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-8-(methyloxy)-9H-purin-6-amine

2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-1H-purin-6-aminetrifluoroacetate (250 mg, 0.684 mmol) and potassium carbonate (236 mg,1.711 mmol) were dissolved in DMF (4 ml) and heated at 60° C. for 1hour. The reaction mixture was cooled to room temperature andphenylmethyl 4-(2-bromoethyl)-1-piperidinecarboxylate (223 mg, 0.684mmol) added. The reaction was then heated to 50° C. for a further 18hours. Phenylmethyl 4-(2-bromoethyl)-1-piperidinecarboxylate (45 mg,0.147 mmol) was added and the reaction heated at 50° C. for a further 18hours. The reaction mixture was diluted with DCM (5 ml) and water (5 ml)and the layers separated using a hydrophobic frit. The aqueous waswashed with further DCM (5 ml) and the combined organics concentrated.The residue was purified by column chromatography, the sample was loadedin dichloromethane onto silica (Si) 20 g and eluted using a gradient of0-100% ethyl acetate in cyclohexane+0-20% methanol over 40 mins. Theappropriate fractions were combined and evaporated in vacuo to give thetitle compound as a yellow glass (114 mg).

LCMS (System B): t_(RET)=2.91 min; MH⁺ 497

Intermediate 80: Phenylmethyl4-{2-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-aminetrifluoroacetate salt and phenylmethyl4-(2-bromoethyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=2.91 min; MH⁺ 497

Intermediate 81:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{2-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.26 min; MH⁺ 363

Intermediate 82:9-[2-(1-Ethyl-4-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand 2-iodoethane. LCMS (System B): t_(RET)=1.28 min; MH⁺ 391

Intermediate 83:2-{[(1S)-1-Methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand 2-iodopropane. LCMS (System B): t_(RET)=1.27 min; MH⁺ 405

Intermediate 84: Phenylmethyl4-{3-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 4-(3-bromopropyl)-1-piperidinecarboxylate. LCMS (System D):t_(RET)=3.39 min; MH⁺ 497

Intermediate 85:2-(Butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{3-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=2.39 min; MH⁺ 363

Intermediate 86: Phenylmethyl4-{3-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-aminetrifluoroacetate salt and phenylmethyl4-(3-bromopropyl)-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=3.51 min; MH⁺ 511

Intermediate 87:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{3-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]propyl}-1-piperidinecarboxylate.

LCMS (System D): t_(RET)=2.30 min; MH⁺ 349

Intermediate 88:9-[3-(1-Ethyl-4-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 2-iodoethane.

LCMS (System D): t_(RET)=3.10 min; MH⁺ 405

Intermediate 89:2-{[(1S)-1-Methylbutyl]oxy}-9-{3-[1-(1-methylethyl)-4-piperidinyl]propyl}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System D): t_(RET)=3.07 min; MH⁺ 419

Intermediate 90: Phenylmethyl4-{4-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 4-(4-bromobutyl)-1-piperidinecarboxylate. LCMS (System B):t_(RET)=3.23 min; MH⁺ 511

Intermediate 91:2-(Butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{4-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.47 min; MH⁺ 377

Intermediate 92: Phenylmethyl4-{4-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-aminetrifluoroacetate salt and phenylmethyl4-(4-bromobutyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=3.20 min; MH⁺ 525

Intermediate 93:2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{4-[6-amino-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.48 min; MH⁺ 391

Intermediate 94:9-[4-(1-Ethyl-4-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand 2-iodoethane.

LCMS (System B): t_(RET)=1.49 min; MH⁺ 419

Intermediate 95: Phenylmethyl4-{4-[6-amino-2-(butylamino)-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 fromN²-butyl-8-methoxy-9H-purine-2,6-diamine trifluoroacetic acid salt andphenylmethyl 4-(4-bromobutyl)-1-piperidinecarboxylate. LCMS (System B):t_(RET)=2.64 min; MH⁺ 510

Intermediate 96:N²-Butyl-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purine-2,6-diamine

A solution of phenylmethyl4-{4-[6-amino-2-(butylamino)-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylateammoniate (372 mg, 0.730 mmol) and 10% palladium on carbon (155 mg,0.146 mmol) in ethanol (5 ml) was hydrogenated at atmospheric pressureand room temperature for 18 hours. The catalyst was filtered throughCelite and the filtrate concentrated in vacuo. The residue was dissolvedin 1:1 MeOH:DMSO (3 ml) and purified by Mass Directed AutoPrep (MethodA). The solvent was dried under a stream of nitrogen in the Radleysblowdown apparatus to give the title compound as a white gum (157 mg).

LCMS (System D): t_(RET)=1.26 min; MH⁺ 376

Intermediate 97:N²-Butyl-9-[4-(1-ethyl-4-piperidinyl)butyl]-8-(methyloxy)-9H-purine-2,6-diamine

Prepared similarly to Intermediate 46 fromN²-butyl-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purine-2,6-diamineand 2-iodoethane.

LCMS (System B): t_(RET)=1.26 min; MH⁺ 404

Intermediate 98: Phenylmethyl 4-(5-bromopentyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 30 from phenylmethyl4-(5-hydroxypentyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=3.82 min; MH⁺ 368/370

Intermediate 99: Phenylmethyl4-{5-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]pentyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 4-(5-bromopentyl)-1-piperidinecarboxylate. LCMS (System B):t_(RET)=3.31 min; MH⁺ 525

Intermediate 100:2-(Butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{5-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]pentyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.55 min; MH⁺ 391

Intermediate 101: 6-(4-Pyridinyl)-5-hexyn-1-ol

4-bromopyridine hydrochloride (5 g, 25.7 mmol) was partitioned betweensodium hydroxide (20 ml, 40.0 mmol) and ethylacetate (3×100 ml). Theorganic layer was separated, dried over Na₂SO₄ and evaporated in vacuo.The resulting oil was dissolved in triethylamine (10 ml) and degassedunder nitrogen. 5-Hexyn-1-ol, (2.8 ml, 25.8 mmol) was added followed bybis(triphenylphosphine)palladium (II) chloride, (200 mg, 0.285 mmol) andcopper(I)iodide (100 mg, 0.525 mmol) and the resulting mixture wasstirred and heated under reflux for 20 mins. when a dark brown sludgewas obtained. The mixture was cooled to rt and partitioned between EtOAc(200 ml) and water (50 ml). The aqueous phase was extracted with EtOAc(2×100 ml), combined the organic extracts, dried (Na₂SO₄), filtered andevaporated in vacuo. The resulting dark brown gum was purified by columnchromatography, the sample was loaded onto silica (100 g) indichloromethane and eluted using a gradient of 0-100% ethyl acetate incyclohexane over 60 mins. The appropriate fractions were combined andevaporated in vacuo to give the title compound as a yellow oil (2.36 g).LCMS (System D): t_(RET)=1.85 min; MH⁺ 176

Intermediate 102: 6-(4-piperidinyl)-1-hexanol

A solution of 6-(4-pyridinyl)-5-hexyn-1-ol (2.36 g, 13.47 mmol) inacetic acid (25 ml) was hydrogenated over platinium (IV) oxide (0.612 g,2.69 mmol) for 72 hours. The mixture was filtered through a Celitecartridge, washed through with acetic acid and then ethyl acetate. Thecombined filtrate and washings were evaporated in vacuo to give a darkbrown oil. The mixture was hydrogenated again as before, this time in100 ml acetic acid for 20 hours. The mixture was filtered through aCelite cartridge, washed through with acetic acid and then ethylacetate. The combined filtrate and washings were evaporated in vacuo togive a dark brown oil. The sample was loaded in methanol and eluted onaminopropyl (NH₂) 70 g using MeOH. The solvent evaporated in vacuo togive the title compound contaminated with 10%6-(4-pyridinyl)-5-hexyn-1-ol as a dark brown gum (2.94 g).

¹H NMR (400 MHz, CDCl₃) δ ppm 3.64 (t, J=6.5 Hz, 2H) 3.49 (s, 1H)3.06-3.16 (m, 2H) 2.55-2.66 (m, 2H) 1.51-1.75 (m, 5H) 1.07-1.44 (m, 13H)

Intermediate 103: Phenylmethyl4-(6-hydroxyhexyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 64 from 6-(4-piperidinyl)-1-hexanol.LCMS (System B): t_(RET)=3.00 min; MH⁺ 320

Intermediate 104: Phenylmethyl 4-(6-bromohexyl)-1-piperidinecarboxylate

Prepared similarly to Intermediate 30 from phenylmethyl4-(6-hydroxyhexyl)-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=4.07 min; MH⁺ 382/384

Intermediate 105: Phenylmethyl4-{6-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]hexyl}-1-piperidinecarboxylate

Prepared similarly to Intermediate 31 from2-(butyloxy)-8-(methyloxy)-9H-purin-6-amine trifluoroacetate andphenylmethyl 4-(6-bromohexyl)-1-piperidinecarboxylate. LCMS (System B):t_(RET)=3.52 min; MH⁺ 539

Intermediate 106:2-(Butyloxy)-8-(methyloxy)-9-[6-(4-piperidinyl)hexyl]-9H-purin-6-amine

Prepared similarly to Intermediate 32 from phenylmethyl4-{6-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]hexyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.63 min; MH⁺ 405

Intermediate 107:2-(Butyloxy)-9-[6-(1-ethyl-4-piperidinyl)hexyl]-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-(butyloxy)-8-(methyloxy)-9-[6-(4-piperidinyl)hexyl]-9H-purin-6-amineand 2-iodoethane.

LCMS (System B): t_(RET)=1.63 min; MH⁺ 433

Intermediate 108:2-(Butyloxy)-9-{6-[1-(1-methylethyl)-4-piperidinyl]hexyl}-8-(methyloxy)-9H-purin-6-amine

Prepared similarly to Intermediate 46 from2-(butyloxy)-8-(methyloxy)-9-[6-(4-piperidinyl)hexyl]-9H-purin-6-amineand 2-iodoethane.

LCMS (System B): t_(RET)=1.71 min; MH⁺ 447

Intermediate 109: 2-Fluoro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

N,O-bis(trimethylsilyl)acetamide (975 ml, 3.988 mol) was added to astirred suspension of 2-fluoro-1H-purin-6-amine (200 g, 1.306 mmol)(available from, for example, AlliedSignal, US) in anhydrousacetonitrile (4 L) in a 10 L controlled lab reactor and the resultingmixture heated to reflux and maintained at that temperature for 2 hours.The circulator was then re-programmed and the reaction mixture cooled to0° C. A solution of tetrahydropyranyl acetate (preparation described inTetrahedron Letters 2006, 47(27), 4741) (282 g, 1.959 mol) in anhydrousacetonitrile (500 ml) was then added slowly via a dropping funnelfollowed by trimethylsilyl trifluoromethanesulfonate (283 ml, 1.567 mol)dropwise via a dropping funnel. No significant exotherm was observed.The circulator temperature was re-adjusted to 10° C. and stirringmaintained for a further 1 hour. The mixture was then quenched byaddition of 1M sodium carbonate (4 L). A solid precipitate was observedand the pH checked to be basic. Additional water was added to thesuspension (1 L) and on standing the layers separated with the aqueouslayer containing significant solid inorganics. The majority of theaqueous and inorganic solid was separated. The organic layer stillcontained significant solid and was cooled to 0° C. with stirring toencourage further precipitation. The solid was the collected byfiltration and the pad was washed very well with water then dried invacuo at 40° C. overnight to give the title compound as a cream colouredsolid (152.8 g).

LCMS (System D): t_(RET)=1.71 min; MH⁺=238

Intermediate 110:2-[(1-Methylethyl)oxy]-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

Sodium t-butoxide (1.30 g, 13.53 mmol) was added to 2-propanol (16.95ml, 220 mmol) portionwise with stirring over 5 minutes.2-Fluoro-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (2 g, 8.43 mmol)was added and the reaction mixture heated and stirred at 50° C. for 4hours and then allowed to cool to room temperature. The reaction mixturewas then diluted with ethyl acetate (75 ml), washed with water (3×25 ml)and the combined aqueous layers extracted again with ethyl acetate (2×25ml). The combined organic layers were dried by passage through ahydrophobic frit, filtered and evaporated to give an off-white solid(2.30 g). This material was dissolved in dichloromethane and purifiedusing an aminopropyl SPE cartridge (70 g) eluted with a 0-100% ethylacetate in cyclohexane gradient. The appropriate fractions were combinedand evaporated to give a white solid (1.6 g) which was further purifiedby column chromatography using a reverse-phase (C₁₈) Flashmaster IIsystem loading in 1:1 MeOH/DMSO and eluting with 0-50% acetonitrile(+0.1% TFA) in water (+0.1% TFA) gradient over 40 minutes collectingfractions in vials containing ca. 2 mL of saturated aqueous sodiumbicarbonate solution. The appropriate fractions were combined, andextracted with dichloromethane (3×100 mL). The combined organic extractswere dried by passage through a hydrophobic frit and evaporated to givethe title compound as a white solid (888 mg).

LCMS (System B): t_(RET)=1.76 min; MH⁺=278

Intermediate 111:8-Bromo-2-[(1-methylethyl)oxy]-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

N-Bromosuccinimide (604 mg, 3.39 mmol) was added to a solution of2-[(1-methylethy)oxy]-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (888mg, 3.20 mmol) in chloroform (30 ml) at 0-5° C. under nitrogen. Themixture was stirred at 0-5° C. for 1 hour during which time it becamereddish brown in colour and it was then warmed to room temperature andstirred for a further 4 hours. LCMS indicated the reaction to beincomplete and more N-bromosuccinimide (114 mg, 0.641 mmol) was addedand the reaction mixture stirred at room temperature overnight. Thereaction mixture was then diluted with chloroform (30 ml), washed withwater (2×20 ml) and the layers were separated using a hydrophobic fritand the organic layer was evaporated to give a red solid (1.16 g). Thismaterial was dissolved in dichloromethane and purified by silica gelchromatography on an SPE cartridge (50 g) using a 0-100% ethyl acetatein cyclohexane gradient as eluent. The appropriate fractions werecombined and evaporated to give the title compound as a pale yellowsolid 712 mg.

LCMS (System B): t_(RET)=2.36 min; MH⁺=356/358.

Intermediate 112:2-[(1-Methylethyl)oxy]-8-(methyloxy)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

To a stirred suspension of8-bromo-2-[(1-methylethyl)oxy]-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine(690 mg, 1.937 mmol) in methanol (15 ml) was added sodium methoxide (30%wt/v solution in methanol, 2.4 ml) and the reaction mixture heated at50° C. for 2 hours. The reaction mixture was then heated to 70° C. andstirred for 2.5 hours. The solvent was evaporated and the residuepartioned between saturated aqueous ammonium chloride solution (15 ml)and ethyl acetate (20 mL). The layers were separated, the aqueous phasewas extracted with additional ethyl acetate (2×10 mL) and the organicextracts were combined, dried by passage through a hydrophobic frit andevaporated to give the title compound as a yellow solid (573 mg).

LCMS (System B): t_(RET)=1.92 min; MH⁺=308.

Intermediate 113: 2-[(1-Methylethyl)oxy]-8-(methyloxy)-1H-purin-6-aminetrifluoroacetate

Trifluoroacetic acid (1 ml, 12.98 mmol) was added to a stirred solutionof2-[(1-methylethyl)oxy]-8-(methyloxy)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine(568 mg, 1.848 mmol) in methanol (10 ml) and the mixture was stirred atroom temperature overnight. More trifluoroacetic acid (0.2 ml) was addedand the reaction mixture stirred at room temperature for a further 1.5hours and then evaporated in vacuo. The solid residue was trituratedwith ethyl acetate, collected by filtration, washed with ethyl acetateand dried in vacuo overnight to give the title compound as a white solid(405 mg).

LCMS (System B): t_(RET)=1.02 min; MH⁺=224

Intermediate 114: 1,1-Dimethylethyl4-{4-[6-amino-2-[(1-methylethyl)oxy]-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate

To a solution of 2-[(1-methylethyl)oxy]-8-(methyloxy)-1H-purin-6-amine(37 mg, 0.166 mmol) in DMF (0.5 ml) was added potassium carbonate (55mg, 0.398 mmol) followed by a solution of 1,1-dimethylethyl4-(4-bromobutyl)-1-piperidinecarboxylate (58 mg, 0.181 mmol) in DMF (0.2ml) and the mixture was stirred at room temperature for 72 hours. Themixture was diluted with dichloromethane (5 ml) and washed with water (5ml). The layers were separated using a hydrophobic frit, the aqueouslayer was extracted again with dichloromethane (5 ml) and the combinedorganic extracts were evaporated. The residue was dissolved in methanol(0.6 ml) and purified by MDAP (Method A). The appropriate fractions werecombined and evaporated under a stream of nitrogen in a blowdownapparatus to give the title compound as a colourless gum (32 mg).

LCMS (System B): t_(RET)=2.82 min; MH⁺=463

Example 16-Amino-2-butoxy-9-[(1-ethyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

2-Butoxy-9-[(1-ethyl-3-piperidinyl)methyl]-8-methoxy-9H-purin-6-amine(99 mg) was dissolved in methanol (2 ml) and 4N hydrogen chloride indioxan (1 ml) added. After 5 hours the reaction mixture was stripped,quenched with water then saturated sodium hydrogen carbonate added, whena solid precipitated. This was filtered, washed with water and dried toyield 81 mg of the title compound as a white solid.

MS calcd for (C₁₇H₂₈N₆O₂)⁺=348

MS found (electrospray): (M+H)⁺=349

¹H NMR ((CD₃)₂SO): δ 9.85 (1H, s), 6.40 (2H, s), 4.14 (2H, t), 3.55 (2H,m), 2.64 (2H, m), 2.26 (2H, m), 2.02 (1H, m), 1.87 (1H, m), 1.73 (1H,m), 1.64 (3H, m), 1.54 (1H, m), 1.38 (3H, m), 0.93 (7H, m).

Example 26-Amino-2-(butylamino)-9-[(1-ethyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

N²-Butyl-9-[(1-ethyl-3-piperidinyl)methyl]-8-methoxy-9H-purine-2,6-diamine(120 mg) was dissolved in methanol (2 ml) and 4N hydrogen chloride indioxan (1 ml) added. After 5 hours the reaction mixture was stripped,quenched with water then made basic with 1M aq potassium carbonate. Theresulting solid was filtered, washed and dried to give the titlecompound as a crystalline solid, yield 86 mg.

MS calcd for (C₁₇H₂₉N₇O)⁺=347

MS found (electrospray): (M+H)⁺=348

¹H NMR ((CD₃)₂SO): δ 9.52 (1H, s), 6.16 (1H, m), 5.95 (2H, s), 3.50 (2H,m), 3.16 (2H, m), 2.64 (2H, m), 2.25 (2H, m), 2.02 (1H, m), 1.85 (1H,m), 1.75-1.58 (2H, m), 1.58-1.42 (3H, m), 1.41-1.22 (3H, m), 0.99-0.85(7H, m).

Example 3 2-(Butyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-aminehydrochloride

4N hydrogen chloride in dioxane (5.3 mL) was added to a solution of1,1-dimethylethyl4-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate(630 mg) in methanol (16 mL). After 4.5 hours at room temperature, thereaction mixture was concentrated and dried under high vacuum.Purification by chromatography on silica gel eluting with a gradient ofchloroform/methanol/water 90:10:1 to 75:25:1 afforded the title compoundas a white solid (404 mg).

¹H NMR (CD₃OD): δ 4.84 (5H, s), 4.27 (2H, t), 3.79 (2H, d), 3.40 (2H,d), 2.96 (2H, t), 2.21 (1H, m), 1.92 (2H, d), 1.75 (2H, m), 1.47-1.60(4H, m), 1.00 (3H, t).

Example 4 2-(Butyloxy)-9-[(3S)-3-piperidinylmethyl]-9H-purin-6-aminehydrochloride

Prepared similarly to Example 3 from 1,1-dimethylethyl(3R)-3-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate.

¹H NMR (CD₃OD): δ 4.28 (2H, t), 3.77 (2H, m), 3.26 (1H, m), 2.87 (1H,m), 2.78 (1H, dd), 2.28 (1H, m), 1.88-1.97 (2H, m), 1.67-1.77 (3H, m),1.46-1.54 (2H, m), 1.38 (1H, m), 0.98 (3H, t).

HRMS: [M+H]⁺ calcd for C₁₅H₂₄N₆O₂=321.2039; found 321.2043.

Example 5 2-(Butyloxy)-9-[(3R)-3-piperidinylmethyl]-9H-purin-6-aminehydrochloride

Prepared similarly to Example 3 from 1,1-dimethylethyl(3S)-3-{[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]methyl}-1-piperidinecarboxylate.

¹H NMR (CD₃OD): δ 4.27 (2H, t), 3.77 (2H, m), 3.30 (2H, m), 2.88 (1H,m), 2.81 (1H, t), 2.30 (1H, m), 1.89-1.98 (2H, m), 1.68-1.77 (3H, m),1.37-1.54 (3H, m), 0.98 (3H, t). HRMS: [M+H]⁺ calcd forC₁₅H₂₄N₆O₂=321.2039; found 321.2043.

Example 6 2-(Butyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-aminehydrochloride

Prepared similarly to Example 3 from 1,1-dimethylethyl4-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate.

¹H NMR (CD₃OD): δ 4.26 (2H, t), 3.88 (2H, m), 3.35 (2H, m), 2.93 (2H,m), 2.08 (2H, m), 1.74 (4H, m), 1.60 (1H, s), 1.48 (2H, dd), 1.42 (2H,m), 0.98 (3H, t).

HRMS: [M+H]⁺ calcd for C₁₆H₂₆N₆O₂=335.2195; found 335.2182.

Example 72-(Butyloxy)-9-[(1-ethyl-4-piperidinyl)methyl]-9H-purin-6-amine

2-(Butyloxy)-9-[(1-ethyl-4-piperidinyl)methyl]-8-(methyloxy)-9H-purin-6-amine(37 mg, 0.102 mmol) was dissolved in methanol (5 ml) and 4M hydrogenchloride in 1,4-dioxane (0.638 ml, 2.55 mmol) and stirred at rt for 5hours. The solvent was removed in vacuo to give a white solid. Thesample was dissolved in methanol and loaded onto an aminopropyl SPE (2g), eluting with methanol. The solvent was removed to give the titlecompound as a white solid (32 mg).

LCMS (System A): t_(RET)=0.64 min; MH⁺ 349

Example 82-(Butyloxy)-9-[2-(1-ethyl-4-piperidinyl)ethyl]-9H-purin-6-amine

Prepared similarly to Example 7 from2-(butyloxy)-9-[2-(1-ethyl-4-piperidinyl)ethyl]-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.27 min; MH⁺ 363

Example 92-(Butyloxy)-9-[3-(1-ethyl-4-piperidinyl)propyl]-9H-purin-6-amine

Prepared similarly to Example 7 from2-(butyloxy)-9-[3-(1-ethyl-4-piperidinyl)propyl]-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.34 min; MH⁺ 377

Example 106-Amino-2-(butyloxy)-9-[4-(1-ethyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-9-[4-(1-ethyl-4-piperidinyl)butyl]-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.46 min; MH⁺ 391

Example 116-Amino-2-(butyloxy)-9-[2-(2-piperidinyl)ethyl]-7,9-dihydro-8H-burin-8-one

Phenylmethyl2-{2-[6-amino-2-(butyloxy)-8-(methyloxy)-9H-purin-9-yl]ethyl}-1-piperidinecarboxylate(425 mg, 0.881 mmol) in ethanol (50 ml) was hydrogenated over palladiumon carbon (187 mg, 0.176 mmol) at ambient temperature over the weekend.The mixture was filtered through a Celite cartridge under N₂, washedwith EtOH and evaporated in vacuo. The residue was purified by MDAP(Method A) but the fractions contained two products. The fractions wereevaporated and material was dissolved in 4 ml 1:1 DMSO:MeOH. A 1 mlportion of this material was re-purified by MDAP (Method A), thefraction containing the expected product of hydrogenation,2-(butyloxy)-8-(methyloxy)-9-[2-(2-piperidinyl)ethyl]-9H-purin-6-aminewas used directly without removal of the solvent.

The crude aqueous solution containing approx 45 mg2-(butyloxy)-8-(methyloxy)-9-[2-(2-piperidinyl)ethyl]-9H-purin-6-amine(45 mg, 0.129 mmol) was treated with a solution of HCl in 1,4-dioxane(0.807 mL, 3.23 mmol, 4 molar solution). This was stirred at ambienttemperature in a capped vial overnight to give a pale solution. Afurther 1 ml of 4 molar HCl solution in 1,4-dioxane was added andstirring continued over the weekend. The yellow reaction solution wasevaporated to dryness under N₂ in a blow down unit. The residue waspurified by MDAP (Method A), appropriate fractions were evaporated underN₂ in a blow down unit to give the title compound as a white solid (23.3mg).

LCMS (System D): t_(RET)=2.12 min; MH⁺ 335

Example 126-Amino-2-(butyloxy)-9-[2-(1-ethyl-2-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-9-[2-(1-ethyl-2-piperidinyl)ethyl]-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.43 min; MH⁺ 363

Example 136-Amino-2-(butyloxy)-9-[3-(2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

2-(Butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amine(41.89 mg, 0.116 mmol) in methanol (3 ml) was treated with 4 molar HClsolution in 1,4-dioxane (0.722 mL, 2.89 mmol) and stirred at ambienttemperature in a capped vial overnight. The clear reaction solution wasblown down under N₂ and then dissolved in 1 ml 1:1 DMSO:MeOH andpurified by MDAP (Method A). The appropriate fraction was evaporatedunder N₂ in a Radleys blow down unit to afford the title compound as awhite solid (31.1 mg).

LCMS (System D): t_(RET)=2.17 min; MH⁺ 349

Example 146-Amino-2-(butyloxy)-9-[3-(1-ethyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

A solution of 1-iodoethane was prepared by dissolving 1 mmole inacetonitrile (1 ml). A portion of this solution (0.12 ml, equivalent to0.12 mmol) was added to a test tube.2-(Butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amine(435 mg, 1.2 mmol) was dissolved in DMF (6.0 ml) and an aliquot (0.5 ml,0.1 mmole) dispensed to the tube. DIPEA (40 μL, 0.23 mmol) was added,and heated to 50° C. for 18 hours. An additional aliquot of 1-iodoethanein acetonitrile (80 uL, 0.08 mmol) (total added 0.2 mmol) and DIPEA (40uL, 0.23 mmol) was added and continued stirring with heat at 50° C. fora further 18 hours. DMSO:MeOH (200 uL) was added, the mixture filteredand purified by Mass Directed AutoPrep (Method A). The solvent wasevaporated in vacuo using the Genevac. The residue was redissolved in asolution of 4M HCl/dioxane (0.2 ml) and allowed to stand at roomtemperature for 4 hours. The solvent was dried under a stream ofnitrogen in the Radleys blowdown apparatus. The material was redissolvedin methanol (0.5 ml) and applied to an aminopropyl SPE (0.1 g, 3 ml,preconditioned in methanol (1.5 ml)). The product was eluted withadditional methanol (1.5 ml). The solvent was removed to give the titlecompound (6 mg).

LCMS (System A): t_(RET)=0.66 min; MH⁺ 377

Example 156-Amino-2-(butyloxy)-9-[3-(1-propyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand 1-iodopropane.

LCMS (System A): t_(RET)=0.77 min; MH⁺ 391

Example 166-Amino-2-(butyloxy)-9-{3-[1-(1-methylethyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System A): t_(RET)=0.73 min; MH⁺ 391

Example 176-Amino-2-(butyloxy)-9-[3-(1-butyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand 1-iodobutane.

LCMS (System A): t_(RET)=0.75 min; MH⁺ 405

Example 186-Amino-2-(butyloxy)-9-{3-[1-(2-methylpropyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand 1-iodo-2-methylpropane.

LCMS (System A): t_(RET)=0.74 min; MH⁺ 405

Example 196-Amino-2-(butyloxy)-9-{3-[1-(3-methylbutyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand 1-bromo-3-methylbutane.

LCMS (System A): t_(RET)=0.78 min; MH⁺ 419

Example 206-Amino-2-(butyloxy)-9-[3-(1-cyclopentyl-2-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand iodocyclopentane.

LCMS (System B): t_(RET)=1.54 min; MH⁺ 417

Example 216-Amino-2-(butyloxy)-9-{3-[1-(cyclopentylmethyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand iodomethylcyclopentane.

LCMS (System A): t_(RET)=0.79 min; MH⁺ 431

Example 226-Amino-2-(butyloxy)-9-{3-[1-(2-cyclohexylethyl)-2-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(2-piperidinyl)propyl]-9H-purin-6-amineand 2-iodoethylcyclohexane.

LCMS (System A): t_(RET)=0.87 min; MH⁺ 459

Example 236-Amino-2-(butyloxy)-9-[(1-propyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

1-Iodopropane (0.1 mmol) was weighed into a vial and an aliquot (0.3 ml,0.1 mmol) of a solution of2-(butyloxy)-8-(methyloxy)-9-(3-piperidinylmethyl)-9H-purin-6-amine (802mg, 2.398 mmol) suspended in DMF (7.2 ml) was added. DIPEA (40 μl, 0.229mmol) was added and the tube was capped and shaken to aid dispersionthen allowed to stand at room temperature (18 hours). An additionalportion of 1-iodopropane (0.05 mmol) was added and the reaction allowedto stand for 18 hours. DMSO (400 uL) was added and the mixture purifiedby Mass Directed AutoPrep (Method A). The solvent was evaporated invacuo using the Genevac. The residue was redissolved in 4M HCl/dioxane(0.5 ml), capped and stood at room temperature for 18 hours. The solventwas dried under a stream of nitrogen in the Radleys blowdown apparatus.The material was redissolved in methanol (0.5 ml), and applied to a 0.5g aminopropyl SPE (preconditioned with methanol, 2 CV). The cartridgewas eluted with methanol (2 ml), the solvent was removed to give thetitle compound (7.5 mg).

LCMS (System A): t_(RET)=0.63 min; MH⁺ 363

Example 246-Amino-2-(butyloxy)-9-{[1-(1-methylethyl)-3-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one

2-Iodopropane (0.1 mmol) was weighed into a vial and an aliquot (0.3 ml,0.1 mmol) of a solution of2-(butyloxy)-8-(methyloxy)-9-(3-piperidinylmethyl)-9H-purin-6-amine (802mg, 2.398 mmol) suspended in DMF (7.2 ml) was added. DIPEA (40 μl, 0.229mmol) was added and the tube was capped and shaken to aid dispersionthen allowed to stand at room temperature (18 hours). DMSO (400 uL) wasadded and the mixture purified by Mass Directed AutoPrep (Method A). Thesolvent was evaporated in vacuo using the Genevac. The residue wasredissolved in 4M HCl/dioxane (0.5 ml), capped and stood at roomtemperature for 18 hours. The solvent was dried under a stream ofnitrogen in the Radleys blowdown apparatus. The material was redissolvedin methanol (0.5 ml), and applied to a 0.5 g aminopropyl SPE(preconditioned with methanol, 2 CV). The cartridge was eluted withmethanol (2 ml), the solvent was removed to give the title compound(11.1 mg). LCMS (System A): t_(RET)=0.62 min; MH⁺ 363

Example 256-Amino-2-(butyloxy)-9-[(1-butyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(3-piperidinylmethyl)-9H-purin-6-amine and1-iodobutane.

LCMS (System A): t_(RET)=0.69 min; MH⁺ 377

Example 266-Amino-2-(butyloxy)-9-{[1-(2-methylpropyl)-3-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(3-piperidinylmethyl)-9H-purin-6-amine and1-iodo-2-methylpropane.

LCMS (System A): t_(RET)=0.67 min; MH⁺ 377

Example 276-Amino-2-(butyloxy)-9-{[1-(3-methylbutyl)-3-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(3-piperidinylmethyl)-9H-purin-6-amine and1-bromo-3-methylbutane.

LCMS (System A): t_(RET)=0.74 min; MH⁺ 391

Example 286-Amino-2-(butyloxy)-9-[(1-cyclopentyl-3-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-onehydrochloride

To a solution of2-(butyloxy)-9-[(1-cyclopentyl-3-piperidinyl)methyl]-8-(methyloxy)-9H-purin-6-amine(37.2 mg, 0.092 mmol) in methanol (3 ml) at room temperature was added4.0 M HCl in 1,4-dioxane (0.578 ml). The reaction mixture was stirred atambient temperature overnight. The reaction solution was evaporatedunder N₂ in a Radleys blow down unit to give the title compound as anoff-white solid (39 mg). LCMS (System B): t_(RET)=1.39 min; MH⁺ 389

Example 296-amino-2-(butyloxy)-9-[2-(3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amine.

LCMS (Method A): t_(RET)=0.75 min; MH⁺ 335

Example 306-Amino-2-(butyloxy)-9-[2-(1-ethyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand 1-iodoethane.

LCMS (System A): t_(RET)=0.65 min; MH⁺ 363

Example 316-Amino-2-(butyloxy)-9-[2-(1-propyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand 1-iodopropane.

LCMS (System A): t_(RET)=0.69 min; MH⁺ 377

Example 326-Amino-2-(butyloxy)-9-{2-[1-(1-methylethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System A): t_(RET)=0.68 min; MH⁺ 363

Example 336-Amino-2-(butyloxy)-9-[2-(1-butyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand 1-iodobutane.

LCMS (System A): t_(RET)=0.74 min; MH⁺ 391

Example 346-Amino-2-(butyloxy)-9-{2-[1-(2-methylpropyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand 1-iodo-2-methylpropane.

LCMS (System A): t_(RET)=0.72 min; MH⁺ 391

Example 356-Amino-2-(butyloxy)-9-{2-[1-(1-ethylpropyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

A solution of 3-bromopentane was prepared by dissolving 1 mmole inacetonitrile (1 ml). A portion of this solution (0.12 ml, equivalent to0.12 mmol) was added to a test tube.2-(Butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amine(435 mg, 1.2 mmol) was dissolved in DMF (6.0 ml) and an aliquot (0.5 ml,0.1 mmol) dispensed to the tube. DIPEA (40 μL, 0.23 mmol) and potassiumcarbonate (46 mg, 0.3 mmol) added, and heated to 50° C. for 18 hr. Anadditional aliquot of 3-bromopentane in acetonitrile (80 uL, 0.08 mmol)(total added 0.2 mmol) and DIPEA (40 uL, 0.23 mmol) was added andcontinued stirring with heat at 50° C. for a further 18 hours. DMSO:MeOH(200 uL) was added, the mixture filtered and purified by Mass DirectedAutoPrep (Method A). The solvent was evaporated in vacuo using theGenevac. The residue was redissolved in a solution of 4M HCl/dioxane(0.2 ml) and allowed to stand at room temperature for 4 hours. Thesolvent was dried under a stream of nitrogen in the Radleys blowdownapparatus. The material was redissolved in methanol (0.5 ml) and appliedto an aminopropyl SPE (0.1 g, 3 ml, preconditioned in methanol (1.5ml)). The product was eluted with additional methanol (1.5 ml). Thesolvent was removed to give the title compound (6 mg).

LCMS (System A): t_(RET)=0.66 min; MH⁺ 377

Example 366-Amino-2-(butyloxy)-9-[2-(1-cyclopentyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand iodocyclopentane.

LCMS (System A): t_(RET)=0.72 min; MH⁺ 403

Example 376-Amino-2-(butyloxy)-9-{2-[1-(cyclopentylmethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand (1-iodomethyl)cyclopentane.

LCMS (System A): t_(RET)=0.78 min; MH⁺ 417

Example 386-Amino-2-(butyloxy)-9-[2-(1-cyclohexyl-3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand iodocyclohexane.

LCMS (System A): t_(RET)=0.77 min; MH⁺ 417

Example 396-Amino-2-(butyloxy)-9-{2-[1-(2-cyclohexylethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 35 from2-(butyloxy)-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amineand (1-iodoethyl)cyclohexane.

LCMS (System A): t_(RET)=0.77 min; MH⁺ 444

Example 406-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-[2-(3-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

To a solution of2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[2-(3-piperidinyl)ethyl]-9H-purin-6-amine(35 mg, 0.097 mmol) in methanol (4 ml) was added 4M HCl in dioxane (1.5ml, 6.00 mmol) and the mixture was allowed to stir at room temperaturefor 1.5 hours. The reaction was then dried under a stream of nitrogen inthe Radleys blowdown apparatus to give the crude product. This wasredissolved in methanol (˜5 mL) and passed down a 2 g aminopropyl (—NH₂)SPE cartridge. The filtrate was dried under a stream of nitrogen inRadleys blowdown apparatus. The sample was dissolved in 1:1 MeOH:DMSO (1ml) and purified by Mass Directed AutoPrep (Method A). The solvent wasdried under a stream of nitrogen in the Radleys blowdown apparatus togive the title compound as an off-white solid (21.5 mg). LCMS (SystemD): t_(RET)=2.25 min; MH⁺ 349

Example 416-Amino-9-[2-(1-ethyl-3-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from9-[2-(1-ethyl-3-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.65 min; MH⁺ 377

Example 426-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-3-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 40 from2-{[(1S)-1-methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-3-piperidinyl]ethyl}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.65 min; MH⁺ 377

Example 436-Amino-2-(butyloxy)-9-[3-(3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.17 min; MH⁺ 349

Example 446-Amino-2-(butyloxy)-9-[3-(1-ethyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand iodoethane.

LCMS (System A): t_(RET)=0.64 min; MH⁺ 377

Example 456-Amino-2-(butyloxy)-9-[3-(1-propyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand 1-iodopropane.

LCMS (System A): t_(RET)=0.68 min; MH⁺ 391

Example 466-Amino-2-(butyloxy)-9-{3-[1-(1-methylethyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System A): t_(RET)=0.67 min; MH⁺ 391

Example 476-Amino-2-(butyloxy)-9-[3-(1-butyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand 1-iodobutane.

LCMS (System A): t_(RET)=0.72 min; MH⁺ 405

Example 486-Amino-2-(butyloxy)-9-{3-[1-(2-methylpropyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-onehydrochloride

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand 1-iodo-2-methylpropane. ¹H NMR (d₆-DMSO) evidence indicated that thematerial obtained was the hydrochloride salt, piperidine NH⁺ at δ 9.42ppm.

LCMS (System A): t_(RET)=0.70 min; MH⁺ 405

Example 496-Amino-2-(butyloxy)-9-{3-[1-(3-methylbutyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand 1-bromo-3-methylbutane.

LCMS (System A): t_(RET)=0.75 min; MH⁺ 419

Example 506-Amino-2-(butyloxy)-9-[3-(1-cyclopentyl-3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand iodocyclopentane.

LCMS (System A): t_(RET)=0.71 min; MH⁺ 417

Example 516-Amino-2-(butyloxy)-9-{3-[1-(cyclopentylmethyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-onehydrochloride

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand iodomethylcyclopentane. ¹H NMR (d₆-DMSO) evidence indicated that thematerial obtained was the hydrochloride salt, piperidine NH⁺ at δ 9.58ppm.

LCMS (System A): t_(RET)=0.77 min; MH⁺ 431

Example 526-Amino-2-(butyloxy)-9-{3-[1-(2-cyclohexylethyl)-3-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amineand (1-iodoethyl)cyclohexane.

LCMS (System A): t_(RET)=0.87 min; MH⁺ 459

Example 536-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-[3-(3-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 13 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[3-(3-piperidinyl)propyl]-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.29 min; MH⁺ 363

Example 546-Amino-9-[3-(1-ethyl-3-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from9-[3-(1-ethyl-3-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.45 min; MH⁺ 391

Example 556-amino-2-(butyloxy)-9-[4-(3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.44 min; MH⁺ 363

Example 566-Amino-2-(butyloxy)-9-[4-(1-ethyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand iodoethane.

LCMS (System A): t_(RET)=0.68 min; MH⁺ 391

Example 576-Amino-2-(butyloxy)-9-[4-(1-propyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand 1-iodopropane.

LCMS (System A): t_(RET)=0.72 min; MH⁺ 405

Example 586-Amino-2-(butyloxy)-9-{4-[1-(1-methylethyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System A): t_(RET)=0.71 min; MH⁺ 405

Example 596-Amino-2-(butyloxy)-9-[4-(1-butyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand 1-iodobutane.

LCMS (System A): t_(RET)=0.76 min; MH⁺ 419

Example 606-Amino-2-(butyloxy)-9-{4-[1-(2-methylpropyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-onehydrochloride

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand 1-iodo-2-methylpropane. ¹H NMR (d₆-DMSO) evidence indicated that thematerial obtained was the hydrochloride salt, piperidine NH⁺ at δ 9.35ppm.

LCMS (System A): t_(RET)=0.74 min; MH⁺ 419

Example 616-Amino-2-(butyloxy)-9-{4-[1-(3-methylbutyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand 1-bromo-3-methylbutane.

LCMS (System A): t_(RET)=0.80 min; MH⁺ 433

Example 626-Amino-2-(butyloxy)-9-[4-(1-cyclopentyl-3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand iodocyclopentane.

LCMS (System A): t_(RET)=0.75 min; MH⁺ 431

Example 636-Amino-2-(butyloxy)-9-{4-[1-(cyclopentylmethyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-burin-8-onehydrochloride

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand (iodomethyl)cyclopentane. ¹H NMR (d₆-DMSO) evidence indicated thatthe material obtained was the hydrochloride salt, piperidine NH⁺ at δ9.45 ppm.

LCMS (System A): t_(RET)=0.80 min; MH⁺ 445

Example 646-Amino-2-(butyloxy)-9-{4-[1-(2-cyclohexylethyl)-3-piperidinyl]butyl}-7,9-dihydro-8H-burin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amineand (2-iodoethyl)cyclohexane.

LCMS (System A): t_(RET)=0.90 min; MH⁺ 473

Example 656-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-[4-(3-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 13 from2-{[(1S)-1-Methylbutyl]oxy}-8-(methyloxy)-9-[4-(3-piperidinyl)butyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.51 min; MH⁺ 377

Example 666-Amino-9-[4-(1-ethyl-3-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from9-[4-(1-ethyl-3-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.54 min; MH⁺ 405

Example 676-Amino-2-(butyloxy)-9-[5-(3-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[5-(3-piperidinyl)pentyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.66 min; MH⁺ 377

Example 686-Amino-2-(butyloxy)-9-[5-(1-ethyl-3-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-9-[5-(1-ethyl-3-piperidinyl)pentyl]-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.67 min; MH⁺ 405

Example 696-Amino-2-(butyloxy)-9-{5-[1-(1-methylethyl)-3-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-9-{5-[1-(1-methylethyl)-3-piperidinyl]pentyl}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.79 min; MH⁺ 419

Example 706-Amino-2-(butyloxy)-9-[(1-propyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine and1-iodopropane.

LCMS (System B): t_(RET)=1.34 min; MH⁺ 363

Example 716-Amino-2-(butyloxy)-9-{[1-(1-methylethyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine and2-iodopropane.

LCMS (System B): t_(RET)=1.32 min; MH⁺ 363

Example 726-Amino-2-(butyloxy)-9-[(1-butyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine and1-iodobutane.

LCMS (System B): t_(RET)=1.45 min; MH⁺ 377

Example 736-Amino-2-(butyloxy)-9-{[1-(2-methylpropyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine and1-iodo-2-methylpropane.

LCMS (System B): t_(RET)=1.43 min; MH⁺ 377

Example 746-Amino-2-(butyloxy)-9-{[1-(3-methylbutyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine and1-bromo-3-methylpropane.

LCMS (System B): t_(RET)=1.25 min; MH⁺ 349

Example 756-Amino-2-(butyloxy)-9-[(1-cyclopentyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 24 from2-(butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine andiodocyclopentane.

LCMS (System B): t_(RET)=1.45 min; MH⁺ 389

Example 766-Amino-2-(butyloxy)-9-[(1-cyclohexyl-4-piperidinyl)methyl]-7,9-dihydro-8H-purin-8-one

Iodocyclohexane (0.1 mmol) was weighed into a tube and an aliquot (0.4ml, 0.12 mmol) of a solution of2-(butyloxy)-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine(0.402 g mg, 1.2 mmol) suspended in DMF (4.8 ml) was added to each tube.DIPEA (40 μl, 0.229 mmol) and potassium carbonate (46 mg) was added toeach tube, the tube was heated at 50° C. for 18 hours. An additionalportion of iodocyclohexane (15 μl) and DIPEA (40 μl) was added andheating continued for a further 18 hours. DMSO (250 uL) was added andthe solution and the mixture purified by Mass Directed AutoPrep (MethodA). The solvent was evaporated in vacuo using the Genevac. The residuewas redissolved in 4M HCl/dioxane (0.2 ml), capped and stood at roomtemperature for 18 hours. The solvent was dried under a stream ofnitrogen in the Radleys blowdown apparatus. The sample was dissolved in1:1 DMSO:MeOH and purified by MDAP (Method C) and the solvent wasevaporated in vacuo using the Genevac. The material was redissolved inmethanol (0.5 ml), and applied to top of 0.1 g aminopropyl SPE(preconditioned with methanol, 1.5 ml). The cartridge was eluted withmethanol (1.5 ml), the solvent was removed to give the title compound(1.9 mg).

LCMS (System B): t_(RET)=1.56 min; MH⁺ 403

Example 776-Amino-2-{[(1S)-1-Methylbutyl]oxy}-9-(4-piperidinylmethyl)-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 40 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.53 min; MH⁺ 335

Example 786-Amino-9-[(1-ethyl-4-piperidinyl)methyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from9-[(1-ethyl-4-piperidinyl)methyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.91 min; MH⁺ 363

Example 796-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-{[1-(1-methylethyl)-4-piperidinyl]methyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-{[1S-1-methylbutyl]oxy}-9-{[1-(1-methylethyl)-4-piperidinyl]methyl}-8-(methyloxy)-9H-purine-6-amine.

LCMS (System D): t_(RET)=2.98 min; MH⁺ 377

Example 806-Amino-2-(butyloxy)-9-[2-(1-propyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

1-Iodopropane (0.1 mmol) was weighed into a vial and an aliquot (0.4 ml,0.12 mmol) of a solution of2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amine(0.418 g mg, 1.2 mmol) suspended in DMF (4.8 ml) was added to each tube.DIPEA (40 μl, 0.229 mmol) was added finally to each tube, the tube washeated at 50° C. for 18 hours. An additional portion of 1-iodopropane(15 μl) and DIPEA (20 μl) was added to each tube and heating continuedfor a further 18 hours. DMSO (200 uL) was added and the solution and themixture purified by Mass Directed AutoPrep (Method A). The solvent wasevaporated in vacuo using the Genevac. The residue was redissolved in 4MHCl/dioxane (0.2 ml), capped and stood at room temperature for 18 hours.The solvent was dried under a stream of nitrogen in the Radleys blowdownapparatus. The material was redissolved in methanol (0.5 ml), andapplied to top of 0.1 g aminopropyl SPE (preconditioned with methanol,1.5 ml). The cartridge was eluted with methanol (1.5 ml) and the solventwas removed to give the title compound (5.1 mg).

LCMS (System B): t_(RET)=1.38 min; MH⁺ 377

Example 816-Amino-2-(butyloxy)-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.27 min; MH⁺ 377

Example 826-Amino-2-(butyloxy)-9-[2-(1-butyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

1-Iodobutane (0.1 mmol) was weighed into a tube and an aliquot (0.4 ml,0.12 mmol) of a solution of2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amine(0.418 g mg, 1.2 mmol) suspended in DMF (4.8 ml) was added. DIPEA (40μl, 0.229 mmol) was added and the tube was heated at 50° C. for 18hours. An additional portion of 1-iodobutane (15 μl) and DIPEA (20 μl)was added and heating continued for a further 18 hours. DMSO (200 uL)was added and the mixture purified by Mass Directed AutoPrep (Method A).The solvent was evaporated in vacuo using the Genevac. The residue wasredissolved in 4M HCl/dioxane (0.2 ml), capped and stood at roomtemperature for 18 hours. The solvent was dried under a stream ofnitrogen in the Radleys blowdown apparatus. The sample was dissolved in1:1 DMSO:MeOH and purified by MDAP (Method C) and the solvent wasevaporated in vacuo using the Genevac. The material was redissolved inmethanol (0.5 ml), and applied to a 0.1 g aminopropyl SPE(preconditioned with methanol, 1.5 ml). The cartridge was eluted withmethanol (1.5 ml), the solvent was removed to give the title compound(4.8 mg).

LCMS (System B): t_(RET)=1.50 min; MH⁺ 391

Example 836-Amino-2-(butyloxy)-9-{2-[1-(2-methylpropyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand 1-iodo-2-methylpropane.

LCMS (System B): t_(RET)=1.47 min; MH⁺ 391

Example 846-Amino-2-(butyloxy)-9-{2-[1-(1-ethylpropyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand 3-bromopentane.

LCMS (System B): t_(RET)=1.53 min; MH⁺ 405

Example 856-Amino-2-(butyloxy)-9-{2-[1-(3-methylbutyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand 1-bromo-3-methylbutane.

LCMS (System B): t_(RET)=1.60 min; MH⁺ 405

Example 866-Amino-2-(butyloxy)-9-[2-(1-cyclopentyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand iodocyclohexane.

LCMS (System B): t_(RET)=1.49 min; MH⁺ 403

Example 876-Amino-2-(butyloxy)-9-{2-[1-(cyclopentylmethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand iodomethylcyclopentane.

LCMS (System B): t_(RET)=1.62 min; MH⁺ 417

Example 886-Amino-2-(butyloxy)-9-[2-(1-cyclohexyl-4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 82 from2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand iodocyclohexane.

LCMS (System B): t_(RET)=1.57 min; MH⁺ 417

Example 896-Amino-2-(butyloxy)-9-{2-[1-(2-cyclohexylethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amineand (1-iodoethyl)cyclohexane.

LCMS (System B): t_(RET)=1.85 min; MH⁺ 445

Example 906-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-[2-(4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 40 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.34 min; MH⁺ 349

Example 916-Amino-9-[2-(1-ethyl-4-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from9-[2-(1-ethyl-4-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.34 min; MH⁺ 377

Example 926-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-{[(1S)-1-methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.51 min; MH⁺ 391

Example 936-Amino-2-(butyloxy)-9-[3-(4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.10 min; MH⁺ 349

Example 946-Amino-2-(butyloxy)-9-[3-(1-propyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 1-iodopropane.

LCMS (System A): t_(RET)=0.70 min; MH⁺ 391

Example 956-Amino-2-(butyloxy)-9-{3-[1-(1-methylethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System A): t_(RET)=0.69 min; MH⁺ 391

Example 966-Amino-2-(butyloxy)-9-[3-(1-butyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 1-iodobutane.

LCMS (System A): t_(RET)=0.75 min; MH⁺ 405

Example 976-Amino-2-(butyloxy)-9-{3-[1-(2-methylpropyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 1-iodo-2-methylpropane.

LCMS (System A): t_(RET)=0.72 min; MH⁺ 405

Example 986-Amino-2-(butyloxy)-9-{3-[1-(1-ethylpropyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-burin-8-one

Prepared similarly to Example 35 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 3-bromopentane.

LCMS (System A): t_(RET)=0.76 min; MH⁺ 419

Example 996-Amino-2-(butyloxy)-9-{3-[1-(3-methylbutyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 1-bromo-3-methylbutane.

LCMS (System A): t_(RET)=0.78 min; MH⁺ 419

Example 1006-Amino-2-(butyloxy)-9-[3-(1-cyclopentyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand iodocyclopentane.

LCMS (System A): t_(RET)=0.73 min; MH⁺ 417

Example 1016-Amino-2-(butyloxy)-9-{3-[1-(cyclopentylmethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand (iodomethyl)cyclopentane.

LCMS (System A): t_(RET)=0.79 min; MH⁺ 431

Example 1026-Amino-2-(butyloxy)-9-[3-(1-cyclohexyl-4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 35 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand iodocyclohexane.

LCMS (System A): t_(RET)=0.78 min; MH⁺ 431

Example 1036-Amino-2-(butyloxy)-9-{3-[1-(2-cyclohexylethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amineand 2-(iodoethyl)cyclohexane.

LCMS (System A): t_(RET)=0.89 min; MH⁺ 459

Example 1046-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-[3-(4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 40 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[3-(4-piperidinyl)propyl]-9H-purin-6-amine.

LCMS (System D): t_(RET)=2.77 min; MH⁺ 363

Example 1056-Amino-9-[3-(1-ethyl-4-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from9-[3-(1-ethyl-4-piperidinyl)propyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=3.10 min; MH⁺ 391

Example 1066-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-{3-[1-(1-methylethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-{[(1S)-1-methylbutyl]oxy}-9-{3-[1-(1-methylethyl)-4-piperidinyl]propyl}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System D): t_(RET)=3.17 min; MH⁺ 405

Examples 1076-Amino-2-(butyloxy)-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.40 min; MH⁺ 363

Example 1086-Amino-2-(butyloxy)-9-[4-(1-propyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 82 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand 1-iodopropane.

LCMS (System B): t_(RET)=1.57 min; MH⁺ 405

Example 1096-Amino-2-(butyloxy)-9-{4-[1-(1-methylethyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 82 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System B): t_(RET)=1.55 min; MH⁺ 405

Example 1106-Amino-2-(butyloxy)-9-[4-(1-butyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 82 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand 1-iodobutane.

LCMS (System B): t_(RET)=1.67 min; MH⁺ 419

Example 1116-Amino-2-(butyloxy)-9-{4-[1-(2-methylpropyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 82 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand 1-iodo-2-methylpropane.

LCMS (System B): t_(RET)=1.64 min; MH⁺ 419

Example 1126-Amino-2-(butyloxy)-9-{4-[1-(1-ethylpropyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

3-Bromopentane (0.1 mmol) was weighed into a tube and an aliquot (0.4ml, 0.12 mmol) of a solution of2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amine(0.452 g mg, 1.2 mmol) suspended in DMF (4.8 ml) was added. DIPEA (40μl, 0.229 mmol) was added and heated at 50° C. for 18 hours. Anadditional portion of 3-bromopentane (15 μl) and DIPEA (40 μl) was addedand heating continued for a further 18 hours. Potassium carbonate (46mg) was added and heating continued for a further 72 hours. DMSO (200uL) was added and the resultant mixture filtered, the solution waspurified by Mass Directed AutoPrep (Method A). The solvent wasevaporated in vacuo using the Genevac. The residue was redissolved in 4MHCl/dioxane (0.2 ml), capped and stood at room temperature for 18 hours.The solvent was dried under a stream of nitrogen in the Radleys blowdownapparatus. The sample was dissolved in 1:1 DMSO:MeOH and purified byMDAP (Method C) and the solvent was evaporated in vacuo using theGenevac. The material was redissolved in methanol (0.5 ml), and appliedto a 0.1 g aminopropyl SPE (preconditioned with methanol, 1.5 ml). Thecartridge was eluted with methanol (1.5 ml), the solvent was removed togive the title compound (5.9 mg).

LCMS (System B): t_(RET)=1.69 min; MH⁺ 433

Example 1136-Amino-2-(butyloxy)-9-{4-[1-(3-methylbutyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 82 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand 1-bromo-3-methylbutane.

LCMS (System B): t_(RET)=1.75 min; MH⁺ 433

Example 1146-Amino-2-(butyloxy)-9-[4-(1-cyclopentyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand iodocyclopentane.

LCMS (System B): t_(RET)=1.65 min; MH⁺ 431

Example 1156-Amino-2-(butyloxy)-9-{4-[1-(cyclopentylmethyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 82 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand iodomethylcyclopentane.

LCMS (System B): t_(RET)=1.77 min; MH⁺ 445

Example 1166-Amino-2-(butyloxy)-9-[4-(1-cyclohexyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 112 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand iodocyclohexane.

LCMS (System B): t_(RET)=1.74 min; MH⁺ 445

Example 1176-Amino-2-(butyloxy)-9-{4-[1-(2-cyclohexylethyl)-4-piperidinyl]butyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 80 from2-(butyloxy)-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amineand (2-iodoethyl)cyclohexane.

LCMS (System B): t_(RET)=1.99 min; MH⁺ 473

Example 1186-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.45 min; MH⁺ 377

Example 1196-Amino-9-[4-(1-ethyl-4-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from9-[4-(1-ethyl-4-piperidinyl)butyl]-2-{[(1S)-1-methylbutyl]oxy}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.45 min; MH⁺ 377

Example 1206-Amino-2-(butylamino)-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 fromN²-butyl-8-(methyloxy)-9-[4-(4-piperidinyl)butyl]-9H-purine-2,6-diamine.

LCMS (System B): t_(RET)=1.17 min; MH⁺ 362

Example 1216-Amino-2-(butylamino)-9-[4-(1-ethyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 fromN²-butyl-9-[4-(1-ethyl-4-piperidinyl)butyl]-8-(methyloxy)-9H-purine-2,6-diamine.

LCMS (System B): t_(RET)=1.19 min; MH⁺ 390

Example 1226-Amino-2-(butyloxy)-9-[5-(4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.52 min; MH⁺ 377

Example 1236-Amino-2-(butyloxy)-9-[5-(1-ethyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand iodoethane.

LCMS (System B): t_(RET)=1.59 min; MH⁺ 405

Example 1246-Amino-2-(butyloxy)-9-[5-(1-propyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand 1-iodopropane.

LCMS (System B): t_(RET)=1.68 min; MH⁺ 419

Example 1256-Amino-2-(butyloxy)-9-{5-[1-(1-methylethyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand 2-iodopropane.

LCMS (System B): t_(RET)=1.66 min; MH⁺ 419

Example 1266-Amino-2-(butyloxy)-9-[5-(1-butyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand 1-iodobutane.

LCMS (System B): t_(RET)=1.78 min; MH⁺ 433

Example 1276-Amino-2-(butyloxy)-9-{5-[1-(2-methylpropyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-onehydrochloride

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand 1-iodo-2-methylpropane. ¹H NMR (d₆-DMSO) evidence indicated that thematerial obtained was the hydrochloride salt, piperidine NH⁺ at δ 9.4ppm.

LCMS (System B): t_(RET)=1.75 min; MH⁺ 433

Example 1286-amino-2-(butyloxy)-9-{5-[1-(3-methylbutyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand 1-bromo-3-methylbutane.

LCMS (System B): t_(RET)=1.86 min; MH⁺ 447

Example 1296-Amino-2-(butyloxy)-9-[5-(1-cyclopentyl-4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand iodocyclopentane.

LCMS (System B): t_(RET)=1.75 min; MH⁺ 445

Example 1306-Amino-2-(butyloxy)-9-{5-[1-(cyclopentylmethyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-onehydrochloride

Prepared similarly to Example 14 from2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amineand iodomethylcyclopentane. ¹H NMR (d₆-DMSO) evidence indicated that thematerial obtained was the hydrochloride salt, piperidine NH⁺ at δ 9.6ppm.

LCMS (System B): t_(RET)=1.87 min; MH⁺ 459

Example 1316-Amino-2-(butyloxy)-9-{5-[1-(2-cyclohexylethyl)-4-piperidinyl]pentyl}-7,9-dihydro-8H-purin-8-onehydrochloride

(2-Iodoethyl)cyclohexane (0.1 mmol) was weighed into a tube and analiquot (0.5 ml, 0.12 mmol) of a solution of2-(butyloxy)-8-(methyloxy)-9-[5-(4-piperidinyl)pentyl]-9H-purin-6-amine(0.435 g mg, 1.2 mmol) suspended in DMF (6 ml) was added. DIPEA (40 μl,0.229 mmol) was added and heated at 50° C. for 18 hours. An additionalportion of 1-iodopropane (80 μl) and DIPEA (20 μl) was added and heatingcontinued for a further 18 hours. DMSO (200 uL) was added and thesolution and the mixture purified by Mass Directed AutoPrep (Method A).The solvent was evaporated in vacuo using the Genevac. The residue wasredissolved in 4M HCl/dioxane (0.2 ml), capped and stood at roomtemperature for 18 hours. The solvent was dried under a stream ofnitrogen in the Radleys blowdown apparatus. The material was redissolvedin methanol (0.5 ml), and applied to a 0.1 g aminopropyl SPE(preconditioned with methanol, 1.5 ml). The cartridge was eluted withmethanol (1.5 ml) and the solvent was removed. The sample wasre-dissolved in 4M HCl in dioxane (100 μl) and evaporated to dryness togive the title compound (2.5 mg). LCMS (System A): t_(RET)=1.04 min; MH⁺487

Example 1326-Amino-2-(butyloxy)-9-[6-(4-piperidinyl)hexyl]-7,9-dihydro-8H-purin-8-onehydrochloride

Prepared similarly to Example 7 from2-(butyloxy)-8-(methyloxy)-9-[6-(4-piperidinyl)hexyl]-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.61 min; MH⁺ 391

Example 1336-Amino-2-(butyloxy)-9-[6-(1-ethyl-4-piperidinyl)hexyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-9-[6-(1-ethyl-4-piperidinyl)hexyl]-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.65 min; MH⁺ 419

Example 1346-Amino-2-(butyloxy)-9-{6-[1-(1-methylethyl)-4-piperidinyl]hexyl}-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from2-(butyloxy)-9-{6-[1-(1-methylethyl)-4-piperidinyl]hexyl}-8-(methyloxy)-9H-purin-6-amine.

LCMS (System B): t_(RET)=1.70 min; MH⁺ 433

Example 1356-Amino-2-[(1-methylethyl)oxy]-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one

Prepared similarly to Example 7 from 1,1-dimethylethyl4-{4-[6-amino-2-[(1-methylethyl)oxy]-8-(methyloxy)-9H-purin-9-yl]butyl}-1-piperidinecarboxylate.

LCMS (System B): t_(RET)=1.17 min; MH⁺ 349

Biological Data

Compounds of the invention were tested for in vitro biological activityin accordance with the following assays, or similar assays:

Assay for the Induction of Interferon-α Using Cryopreserved HumanPeripheral Blood Mononuclear Cells (PBMCs) Compound Preparation

Compounds were dissolved in DMSO. Serial 2-fold dilutions with DMSO wereprepared and 0.25 μl dispensed into 384-well clear Greiner polypropyleneplates.

Preparation of PBMCs

Blood samples of up to 200 ml were obtained from healthy human donors.Whole blood in 25 ml volumes was overlaid onto 15 ml Ficoll gradients inLeucosep tubes, and centrifuged at 1000 g for 20 min. Cells in the bandat the plasma/histopaque interface were carefully removed and washedtwice with PBS (centrifuged at 400 g for 5 min to harvest). The finalpellet was resuspended in freezing medium (90% Heat-inactivated serum,10% DMSO) to a cell concentration of 4×10⁷ cells/ml. The resuspendedcells were then cryopreserved (frozen) using a rate controlled freezer,and stored at −140° C. for up to 4 months.

Incubation and Assay for Interferon-α

Immediately prior to assay, vials of cryopreserved (frozen) PBMCs werethawed rapidly in a water bath at 37° C. A 1:10 dilution of the cells intrypan blue was prepared and counted. The PBMCs were then diluted ingrowth media [RPMI 1640 containing 10% fetal calf serum (invitrogen),Penicillin+Streptavidin (Gibco cat. #25030-024, 1:50), L-Glutamine 2 mM,and 1000 units/ml recombinant human IFN-gamma (Preprotech catalogue#300-02)] to a density of 1×10⁶ cells/ml, and 50 ul/well dispensed to384-well clear Greiner polypropylene plates containing 0.25 μl DMSO ortest compound in 0.25 μl DMSO. Top final concentration of compound wastypically 50 uM or 5 uM (to obtain curve fit for highly activecompounds). Plates were incubated for 24 h at 37° C. in 5% CO₂.

A multi-isoform immunoassay was used to quantify IFN-α in PBMCsupernatants. Rabbit polyclonal antibody against human IFN-α (cataloguenumber 31101, Stratech Scientific) was diluted 1:10000 in assay buffer(RPMI 1640 containing 10% fetal calf serum, Invitrogen) and 20 μl wasadded to each well of an MSD (Meso-Scale Discovery) single small-spot384-well GAR (goat anti-rabbit antibody coated) plate. The plate wasincubated for 1 hour at room temperature with vigorous shaking.Following three washes with PBS, 20 μl of cell supernatant were added toeach well of the plate. The plate was then incubated for 1 hour at roomtemperature with vigorous shaking. A pair of monoclonal antibodies toIFN-α (catalogue numbers 21100 and 21112, Stratech Scientific) werelabelled with sulfo-TAG (MSD), diluted 1:1000 in assay buffer and 20 μladded to each well of the plate. The plate was further incubated for 1hour at room temperature with vigorous shaking. Following three washeswith PBS, 30 μl of x2 T buffer (MSD) was added to each well and theplate was read on an MSD Sector 6000 plate reader.

Data were normalised to internal plate controls of 1 uM resiquimod(n=16) and DMSO (n=16). pEC50 values were derived by 4-parameter curvefit with IRLS in ActivityBase, from 11-point, two-fold serial dilutionof test compounds.

Results

Examples 1 to 135 have been shown to have mean pEC₅₀ of >5.8.

Assay for the Induction of Interferon-α and TNF-α Using Fresh HumanPeripheral Blood Mononuclear Cells (PBMCs) Compound Preparation

Compounds were dissolved and serially diluted in DMSO to give 100× therequired concentration range using a Biomek 2000. 1 ul of test compoundwas transferred into 96-well tissue culture plates using a Biomek FX.Each compound was assayed in duplicate for each donor. Each platecontained a dilution series of the TLR7/8 agonist resiquimod as standardand Column 11 contained 1 μl of 200 μM resiquimod (giving a 2 μM finalconcentration, used to define the approximate maximal response toresiquimod).

Preparation of PBMCs

Blood samples from two human donors were collected into sodium heparin(10 U/ml). 25 ml volumes of whole blood were overlaid onto 15 mlsHistopaque in Leucosep tubes which were centrifuged at 800 g for 20 minand the band at the plasma/histopaque interface carefully removed. Thecollected cells were centrifuged at 2500 rpm for 10 min. and the pelletresuspended in 10 ml of media (RPMI 1640 (Low endotoxin) supplementedwith 10% v/v foetal calf serum (FCS, low endotoxin) 100 U/ml penicillinG, 100 μg/ml streptomycin, 10 mM L-glutamine and 1× non-essential aminoacids). A 1:20 dilution of the cells was prepared using trypan blue &the cells counted using a haemocytometer. The PBMCs were diluted to givea final concentration of 2×10⁶/ml and 100 ul of this cells suspensionwas added to wells containing 1 μl of diluted test compound.

Incubation and Assays for Interferon-α and TNF-α

The cell preparations were incubated for 24 hr. (37° C., 95% air, 5%CO₂) after which a sample of the supernatant was removed using theBiomek FX and assayed for both IFN-α and TNF-α using the MSD (MesoscaleDiscovery) electrochemiluminescence assay platform. The IFN-α assay wascarried out similarly to that described above. The TNF-α assay wascarried out as per kit instructions (Cat No K111BHB).

Cytokine released was expressed as a percentage of the 2 μM resiquimodcontrol (column 11). This percentage was plotted against compoundconcentration and the pEC50 for the response determined by non-linearleast squares curve fitting. For the IFN-α responses generally a 4parameter logistic model was selected. For the TNF responses where aclear maximum response was obtained (i.e. a well defined plateau in theresponse was observed) then a 4 parameter model was generally used. Ifthe upper asymptote of the curve wasn't well defined then the curvefitting was generally constrained to a maximal response of 100% (i.e.,to the response to 2 μM resiquimod) or to the response of the highestconcentration tested if this was greater than the resiquimod response.Some curves were bell shaped for one or both cytokines and the cytokinedata on the down slope of the bell shaped response (i.e. concentrationsabove those giving the maximal response) were generally excluded fromthe fit, usually with the exception of the concentration immediatelyabove the peak response. Curve fitting thus concentrated on the up slopeof the dose response curve.

Results

Examples 1, 7, 8, 23, 24, 29, 81, and 135 showed mean pEC₅₀s forinduction of IFN-α and TNF-α of >7 and <6 respectively.

Examples 9, 10, 30, 69, 92, 95, and 102 showed mean pEC₅₀s for inductionof IFN-α and TNF-α of >8 and <6 respectively.

Examples 32, 38, 94, 96, and 108 showed mean pEC₅₀s for induction ofIFN-α and TNF-α of >9 and <6 respectively.

Examples 18, 41, 42, 66, 91, 104, 106, 119, and 122 showed mean pEC₅₀sfor induction of IFN-α and TNF-α of >9.5 and <7.5 respectively.

Allergen-Driven Cytokine Assay Using Fresh Human Peripheral BloodMononuclear Cells (PBMCs) from Atopic Volunteers

An assay based on co-culture of atopic human donor derived peripheralblood mononuclear cells (PBMCs) with allergen and test compounds wasdeveloped. After 5-6 days culture, cell supernatants were assayed for arange of cytokines.

Compound Preparation

Compounds were dissolved in DMSO, then serially diluted in growth medium(RPMI 1640 medium supplemented with 100 U/ml penicillin G, 100 μg/mlstreptomycin, 10 mM L-glutamine) to give 4× the required concentrationrange in the presence of 0.04% DMSO. Each compound was assayed intriplicate at all concentrations.

Preparation of PBMCs

Defibrinated human blood from volunteers known to be allergic to Timothygrass was centrifuged at 2500 rpm for 15 minutes. The upper layer ofserum was collected and heat-inactivated at 56° C. for 30 minutes(HI-autologous serum). The lower layer of cells was resuspended in 50 mlPBS (+Ca +Mg), 25 ml diluted blood were overlaid onto 20 ml Lymphoprepin 50 ml tubes then centrifuged at 2500 rpm for 20 minutes at RT. Theband at the serum/Lymphoprep interface was carefully removed. Thecollected cells were washed with PBS and re-suspended at 4×106/ml ingrowth medium with HI-autologous serum. PBMCs were seeded at 0.4×106cells/well in flat-bottomed 96 well plates in the presence of 10 μg/mlTimothy grass antigen (Alk Abello) and test compounds at appropriateconcentrations in a total volume of 200 ul.

Incubation and Cytokine Assays

Plates were incubated at 37° C. in 5% CO₂ for up to 6 days. The cellmedium from each well was harvested and stored at −20° C. prior toanalysis. Cytokines and chemokines in supernatants were detected usingMeso Scale Discovery 10 spot plates for Human TH1/Th2 cytokines.

In the above assay, data from separate studies with PBMCs from at leasttwo allergic donors, Examples 8, 9, 10 and 92 were shown to reduceproduction of the Th2 cytokines IL-5 and IL-13 in a dose response mannerwith ≧50% reduction observed at ≦0.008 μM for IL-5 and ≦0.04 μM forIL-13 compared to the allergen control.

1-15. (canceled)
 16. A method of treatment of allergic diseases andother inflammatory conditions for example allergic rhinitis and asthma,infectious diseases, and cancer which method comprises administering aneffective amount of a compound of formula (I):

wherein; R¹ is C₁₋₆alkylamino, or C₁₋₆alkoxy; R² is a group having thestructure:

n is an integer having a value of 1 to 6; Het is a 6-membered saturatedheterocycle containing one nitrogen atom wherein Het is attached to the—(CH₂)_(n)— moiety at any carbon atom of the heterocycle; R³ ishydrogen, C₁₋₈alkyl, or C₃₋₇cycloalkylC₀₋₆alkyl; or a pharmaceuticallyacceptable salt thereof.
 17. A compound of formula (I′):

wherein; R^(1′) is C₁₋₆alkylamino, or C₁₋₆alkoxy; R^(2′) is a grouphaving the structure:

n′ is an integer having a value of 1 to 6; Het′ is a 6-memberedsaturated heterocycle containing one nitrogen atom wherein Het′ isattached to the —(CH₂)_(n′)— moiety at any carbon atom of theheterocycle; R^(3′) is hydrogen, C₁₋₈alkyl, or C₃₋₇cycloalkylC₀₋₆alkyl;or a salt thereof; with the proviso that a compound of formula (I′) isnot 2-butoxy-7,8-dihydro-9-[2-(piperidin-2-yl)ethyl]-8-oxoadenine.
 18. Acompound according to claim 17, or a salt thereof, wherein R^(1′) isn-butyloxy.
 19. A compound according to claim 17, or a salt thereof,wherein R^(1′) is (1S)-1-methylbutoxy.
 20. A compound according to claim17, or a salt thereof, wherein n′ is 2, 3, or
 4. 21. A compoundaccording to claim 17, or a salt thereof, wherein R^(3′) is ethyl.
 22. Acompound according to claim 17, or a salt thereof, wherein R^(3′) is1-methylethyl.
 23. A compound according to claim 17, or a salt thereof,wherein R^(3′) is hydrogen.
 24. A compound according to claim 17, or asalt thereof, wherein R^(3′) is n-propyl.
 25. A compound or a saltthereof selected from the list consisting of:6-amino-2-(butyloxy)-9-[4-(1-ethyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;6-amino-9-[2-(1-ethyl-4-piperidinyl)ethyl]-2-{[(1S)-1-methylbutyl]oxy}-7,9-dihydro-8H-purin-8-one;6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-{2-[1-(1-methylethyl)-4-piperidinyl]ethyl}-7,9-dihydro-8H-purin-8-one;6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[3-(4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-{3-[1-(1-methylethyl)-4-piperidinyl]propyl}-7,9-dihydro-8H-purin-8-one,and;6-amino-2-(butyloxy)-9-[4-(1-propyl-4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;and salts thereof.
 26. A compound or a salt thereof selected from thelist consisting of:2-(butyloxy)-9-(4-piperidinylmethyl)-9H-purin-6-amine hydrochloride;2-(butyloxy)-9-[2-(4-piperidinyl)ethyl]-9H-purin-6-amine hydrochloride;6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[2-(4-piperidinyl)ethyl]-7,9-dihydro-8H-purin-8-one;6-amino-2-(butyloxy)-9-[3-(4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[3-(4-piperidinyl)propyl]-7,9-dihydro-8H-purin-8-one;6-amino-2-(butyloxy)-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;6-amino-2-{[(1S)-1-methylbutyl]oxy}-9-[4-(4-piperidinyl)butyl]-7,9-dihydro-8H-purin-8-one;6-amino-2-(butyloxy)-9-[5-(4-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one,and;6-amino-2-(butyloxy)-9-[6-(4-piperidinyl)hexyl]-7,9-dihydro-8H-purin-8-onehydrochloride; and salts thereof.
 27. A compound as defined in claim 16,or a pharmaceutically acceptable salt thereof, for use in therapy.
 28. Acompound as defined in claim 16, or a pharmaceutically acceptable saltthereof, for use in the treatment of allergic diseases and otherinflammatory conditions.
 29. A method of treatment of allergic diseasesand other inflammatory conditions, which method comprises administeringto a human subject in need thereof a therapeutically effective amount ofa compound as defined in claim 16, or a pharmaceutically acceptable saltthereof.
 30. A pharmaceutical composition comprising a compound asdefined in claim 16, or a pharmaceutically acceptable salt thereof, andone or more pharmaceutically acceptable diluents or carriers.
 31. Amethod of treating or preventing disease comprising the administrationto a patient human subject suffering from or susceptible to disease, avaccine composition comprising an antigen or antigen composition and acompound as defined in claim 16, or a pharmaceutically acceptable saltthereof.
 32. Use of a compound as defined in claim 16, or apharmaceutically acceptable salt thereof, for the manufacture of amedicament for the treatment of allergic diseases and other inflammatoryconditions.